Positioning device

ABSTRACT

A positioning device is used to accurately position payload devices coupled to the positioning device. The positioning device includes a housing, a tilt shaft that extends through one side or two sides of the housing. The payloads are coupled to the exposed ends of the tilt shaft and a tilt bearing is mounted between the tilt shaft and the housing. The tilt shaft position is controlled by a tilt motor that engages a toothed tilt belt to rotate the tilt shaft bearing. A pan bearing is mounted between the housing and a pan shaft. The rotational position of the housing is controlled by a pan motor which engages a toothed pan belt to rotate the housing. By controlling the pan and tilt, the payloads can be accurately moved to any rotational position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/640,141, “POSITIONING DEVICE,” filed on Apr. 30, 2012; U.S.Provisional Patent Application No. 61/800,537, “Positioning Device,”filed Mar. 15, 2013; and U.S. Provisional Patent Application No.61/801,834, “POSITIONING DEVICE WITH QUICK ATTACH DETACH MOUNTING, WITHSHAFT MISALIGNMENT COMPENSATION AND BELT TENSIONING LOCK MECHANISM,”filed Mar. 15, 2013, which are hereby incorporated by reference in theirentirety.

FIELD OF THE INVENTION

The present invention relates generally to robotic positioning devicesand more particularly to a device for rotatably positioning one or morepayload devices about one or more rotational axes.

BACKGROUND

Robots are machines that can perform tasks automatically or withguidance, typically by remote control. A robot is usually anelectro-mechanical machine that is guided by computer and electronicprogramming. Robots can be autonomous, semi-autonomous or remotelycontrolled. When a human cannot be present on site to perform a jobbecause it is dangerous, far away, or inaccessible, teleoperated robots,or ‘telerobots’ can be used. Rather than follow a predetermined sequenceof movements, a telerobot is controlled from a distance by a humanoperator. The robot may be in another room or another country. Theevolution of the robots will progressively increase autonomous control,such as motion-activated tracking and only streaming video pertinent toa security force. These autonomous artificial intelligence controls canbe generated from remote computers, externally attached computers, andfrom the electronics enclosed within the robot.

In order to perform specific tasks in hazardous environments, robots canhave device appendages—also known as ‘payloads’—which perform requiredtasks. Payloads can be cameras, distance sensors, firearms, mechanicalarms, sensors, etc. In many cases, the payloads must be preciselypositioned or aimed to perform their tasks. Mechanical assembliesintegral to the robot are used to move the payloads. The mechanicaldrive mechanisms used by robots have been geared systems such as spur,harmonic, and worm gears; however, many of these systems are verycomplex, requiring many components to perform precise positioning andare very heavy due to the large number of components. Such heft isburdensome in the growing market for mobile positioning platforms, whilecomplex and fragile geared drives have high incidences of snapped gearteeth and dislodged roller chains under the high vibration and shockexperience by mobile deployed equipment. High vibration will alsoexcessively wear the gear teeth, increasing backlash cumulatively untilthe accuracy is degraded beyond what the user can tolerate. Addingmotors, elastic bands, or other pre-loading mechanisms to counteractbacklash increases parts, complexity, size, weight and cost.

What is needed is an improved positioning system that can provide therequired accuracy and reliability, including performance characteristicsfor operation in environments with high exposure to mechanical shock andvibration; reduced wear in gear teeth and other driveline components;reduced backlash for improved position accuracy; integration ofcomponents to reduce cost, size and complexity; and simplified assemblyand disassembly for manufacturing and maintenance. The simplified designcan have a housing with reduced seams, which is stronger and has fewerseals for environmental and electromagnetic threats to ingress anddamage sensitive electronics.

SUMMARY OF THE INVENTION

The present invention is directed towards a high precision roboticpositioning platform enabling precise aiming and movement of payloadsunder control of one or more users. The positioning device can include abase to which it is mounted. Bases can be an immobile tripod, tall pole,edifice, or fixture in a factory assembly line, or bases can be mobilemanned or unmanned vehicles, satellites, animals, or humans. A shaft isrigidly mounted to the base, and can be a semi-permanent mount or caninclude a toggle clamping assembly for repeated and rapid installationand removal of the positioning device from the base. A housing canrotate about the fixed shaft via enclosed drive components. The drivecomponents can include a motor or actuator (“motor”); bearings; pulleysor gears (“gear”); and a belt, cable, roller chain, or similar linkageto transfer torque between gears. The motor can be rigidly mounted tothe housing and can rotate a pulley or pinion gear (“motor gear”)directly from the coupled motor rotor or indirectly via an intermediarygearbox. This motor gear is coupled to another gear rigidly mounted tothe fixed shaft (“shaft gear”), and the inter-gear coupling can be adirect meshing of the two gears' teeth or an indirect coupling via achain, cable, or belt.

In a belt drive, the belt can be any one of a variety of belt toothprofiles such as trapezoidal, curvilinear, or modified curvilinear toothprofile, and both the motor gear and shaft gear can have a mating grooveprofile for proper mesh with the chosen belt. The teeth of the belt andgrooves of the gear can be matching profiles or slightly different,corresponding mating profiles. The modified curvilinear belt profile canhave curved sides and valleys but has flat peaks that do not fill thecurved valleys of the mating pulley profile like traditional curvilinearprofiles. While the belt can have cut-off peaks, the pulley toothpattern can be fully curved and the connection between the belt and theteeth can be a “mating” design rather than an exact “matching” designfound in trapezoidal and standard curvilinear profiles.

The housing of the positioning device can rotate smoothly about thefixed shaft via a bearing rigidly coupled between the shaft and housing.The bearing can have an inner ring, an outer ring and rolling or glidingbearings that are held between the inner ring and the outer ring. Thehousing can be rigidly coupled to either ring of the bearing. In orderto provide rigidity against static and dynamic loads in axial, radial,moment, and combined directions, the bearing can have a four pointcontact with the inner ring and outer ring and be under a pre-load tominimize undesired play in the bearing elements. The bearing cansimultaneously serve as both a bearing and rotary shaft gear in the samepackage when a four point contact or similarly robust bearingarrangement includes gearing on the external ring; small bearings withexternal gearing can be described as miniature slew bearings orexternally geared turntable bearings.

The shaft gear can be a miniature slew bearing or externally gearedturntable bearing and have an outer diameter of less than 12 inches andeach weighing less than 5 pounds. The inventive design can also bescaled up to support a heavier housing and payloads, and can adoptbearing element and race configurations with performance attributes moresuited to larger, heavier loads than the 4-pt ball bearingconfiguration. Larger bearing rings can adopt weight-saving constructionmaterials such as aluminum, beryllium, and magnesium alloys whilevarious other materials and blends can be selected, notably carbonnanotube doped materials, to optimize other performance metrics. Furtherweight savings can be achieved with new materials in the rolling bearingelements; for example, either balls or cylindrical rollers constructedof silicon nitride.

Payloads can be rigidly coupled to the housing and precisely rotatedalong with the housing about the fixed axis by control of the motor anddrive components. To accommodate payloads which must not rotate with thehousing, a ‘pan-through shaft’ configuration can be adopted. If thebearing is mounted around the shaft on one side of the housing, a secondbearing or bushing can be mounted around the shaft on a second side ofthe housing opposite the first side. This secondary bearing can have aloose fit on the shaft to delegate axial loads to the more capableturntable bearing. The bearings and shaft components can align to eachother with keyways and precisely located alignment pins, and anintermediary shaft coupler can compensate for any remaining shaftmisalignment. The fixed shaft can be extended completely through thesecond side of the housing and payloads can be coupled to the end of thefixed shaft for a mounting stationary with the fixed base and thus freeof the housing's rotary motion.

The positioning device can also include a second shaft which extendsthrough holes in one or more sides of the positioning device housing torotate coupled payloads about a second axis. This shaft can be anorthogonal or canted axis to the fixed shaft axis, rotating relative tothe housing and free of the fixed mounting base. Commonly the mountingplatform is approximately level to the earth, with the fixed shaftrising upward, the housing rotating in azimuth about the fixed shaft topan payloads left and right. The secondary orthogonal shaft thus canrotate up/down in elevation to tilt payloads at high and low angles.Such dual-axis positioners are known as ‘pan-tilts’ or gimbals. Thetilting shaft (“tilt shaft”) and drive components can include many ofthe same structures, components, and methods used for the fixed azimuthshaft (“pan shaft”). Each component and assembly of the pan shaft andpan drive assembly can have a corresponding tilt component or tiltassembly performing substantially the same role accomplished by itsfixed-shaft counterpart described earlier; however, translated to anorthogonal or canted angle.

The tilt shaft can be coupled to a bearing. Like the pan bearing, thetilt bearing can have an inner ring, an outer ring and four pointcontact bearings that are held between the inner ring and the outerring. In an embodiment, the inner ring can be rigidly coupled to thehousing of the positioning device and the outer ring of the tilt bearingcan be rigidly coupled to the tilt shaft. If the tilt bearing is mountedaround the tilt shaft on one side of the housing, a second bearing orbushing can be mounted with a loose fit around the tilt shaft on asecond side of the housing opposite the first side. The tilt shaft canpenetrate through a second side of the housing in a similar manner tothe pan-through-shaft configuration to couple a second tilt payload tothe end of the tilt shaft. The shaft can be split and can include anintermediary shaft coupler to compensate for shaft misalignment. Thepositioning device can include a tilt drive mechanism that includes atilt motor coupled to a tilt belt that surrounds the outer ring of thetilt bearing. The outer ring can include teeth to serve dual-duty as atilt shaft gear, such teeth engage corresponding teeth in the belt and atilt motor gear.

To ensure the belt is consistently installed with the proper tension,and ensure the belt maintains tension throughout service in highvibration and shock environments, the motors can be mounted to slidingplates which lock down with bolts and can include a ratcheting geartrack or wedge vise to incrementally position the plates and support thebolts in holding the factory-set belt tension.

The electrical power can be supplied by an internal battery that can berecharged or replaced infrequently; an external electrical power sourcesuch as grid electrical power or power over fiber-optic; a localgenerator such as solar, wind, hydro, etc.; or directed energytransmission such as microwave or free-space laser beamed power.

Users can be human, artificial intelligence (‘AI’) computers, cyberneticorganisms (‘cyborg’), or collective networks of any combination ofdistinct human, cyborg, or AI computers. Human users can operate orposition payloads via human computer interface devices (‘HIDs’) such asanalog knobs, keyboards, joysticks, gamepads, touch screens, voicerecognition microphones, gesture recognition vision systems orthought-sensing brain scanners. These HIDs can transmit signals or adata protocol to interface a central electronic control system(“controller”) onboard the positioning device that interprets thecommands as instructions to pan, tilt, zoom, or perform other actions.Cyborgs would be anticipated to use direct data links between thecontroller and their computerized brain via any suitable signaltransmission media, while also being able to use their bodies tointerface the controller via HIDs.

AI users can be software running on a computer linked to the pan-tiltdevice externally, or can be integrated into the pan-tilt device,logically embedded into the controller housed inside the robotic deviceenclosure, or loaded onto the computer subsystem of a payload. Anynumber and combination of complex AI or simple software algorithms canoperate on a hierarchal basis or as a collaborative collective ofresources and processing nodes distributed over a computer network; thepayloads and positioning device being networked nodes through which thecomputer network controlling nodes can use the positioning device andpayloads to collect sensory data and physically interact with theenvironment. Requests or commands sent to the positioning devicecontroller by an external controlling node can be wired or wireless,such as radio frequency or laser beamed signals. The positioning devicecontroller can translate or forward external requests in the requiredprotocol or commutation method to the motor(s). Control electronicsinside payloads can also transmit data between the payloads andpositioning controller and on to the remote nodes. The payloads can bedigital cameras, sensors, spotlights, weaponry, etc. The signals fromthese payloads can be transmitted through the positioning system, to thecontroller which can transmit the signals to the remote units andoperators.

Human, cyborg, and AI users can control the positioning device throughnetworks, and can collaborate and share resources through a cloudnetwork; for example, an onboard AI within the positioning device can betasked with analyzing payload sensors in real-time to detect andcognitively realize events of interest. Video clips and telemetry ofinterest can be uploaded to a database within a secure cloud, and otherhuman or AI operators can assume control of the positioning device toinvestigate further and/or perform secondary data mining of theinformation received from it. An integrated battlespace monitoringapplication on another cloud resource may fuse the information frommultiple positioning devices to view individual targets from multiple,overlapping angles or to secure wide areas. In another application ofthe invention where payloads can include mechanical arms and cameras, ateam of doctors can assist patients remotely. Often patients are locatedwithin a hostile zone and a robust unmanned ground vehicular robot mustendure high vibration, impacts, and harsh weather en route to thepatients, then enable doctors precision motion to inspect wounds andmanipulate surgical tools.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top view of an embodiment of the positioningsystem;

FIG. 2 illustrates a front view of an embodiment of the positioningsystem;

FIG. 3 illustrates a side view of an embodiment of the positioningsystem;

FIG. 4 illustrates an electrical power and control systems diagram ofthe positioning system;

FIG. 5 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 6 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 7 illustrates a top cross sectional view of an embodiment of thepositioning system;

FIG. 8 illustrates a top cross sectional view of an embodiment of thepositioning system;

FIG. 9 illustrates a top cross sectional view of an embodiment of thepositioning system;

FIG. 10 illustrates a top cross sectional view of an embodiment of thepositioning system;

FIG. 11 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 12 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 13 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 14 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 15 illustrates a top cross sectional view of an embodiment of thepositioning system;

FIG. 16 illustrates a top cross sectional view of an embodiment of thepositioning system;

FIG. 17 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 18 illustrates a top plan view of an embodiment of the positioningsystem;

FIG. 19 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 20 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 21 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 22 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 23 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 24 illustrates a partial top plan view of an embodiment of thepositioning system;

FIG. 25 illustrates a partial top plan view of an embodiment of thepositioning system;

FIG. 26 illustrates a partial top plan view of an embodiment of thepositioning system;

FIG. 27 illustrates a partial top plan view of an embodiment of thepositioning system;

FIG. 28 illustrates a complete top plan view of an embodiment of thepositioning system;

FIG. 29 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 30 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 31 illustrates a partial top plan view of an embodiment of thepositioning system;

FIG. 32 illustrates a partial top plan view of an embodiment of thepositioning system;

FIG. 33 illustrates a complete top plan view of an embodiment of thepositioning system;

FIG. 34 illustrates a front cross sectional view of an embodiment of thepositioning system;

FIG. 35 illustrates a top plan view of an embodiment of the positioningsystem;

FIG. 36 illustrates a top plan view of an embodiment of a turntablebearing;

FIG. 37 illustrates a front cross sectional view of an embodiment of theturntable bearing;

FIG. 38 illustrates a front cross sectional view of an embodiment of theturntable bearing;

FIG. 39 illustrates a front cross sectional view of an embodiment of theturntable bearing;

FIG. 40 illustrates a front cross sectional view of an embodiment of theturntable bearing;

FIG. 41 illustrates a partial front cross sectional view of anembodiment of the turntable bearing;

FIG. 42 illustrates a partial front cross sectional view of anembodiment of the turntable bearing;

FIG. 43 illustrates a partial front cross sectional view of anembodiment of the turntable bearing;

FIG. 44 illustrates a partial front cross sectional view of anembodiment of the turntable bearing;

FIG. 45 illustrates a partial front cross sectional view of anembodiment of the turntable bearing;

FIG. 46 illustrates a partial front cross sectional view of anembodiment of the turntable bearing;

FIG. 47 illustrates a front cross sectional view of an embodiment of adynamic shaft seal;

FIG. 48 illustrates a front sectional view of a motor mount with a geartrack tensioner;

FIG. 49 illustrates a top-down sectional view of the pawl-gear interfaceof the motor mount;

FIG. 50 illustrates an underneath sectional view of the pawl-gearinterface of the motor mount;

FIG. 51 illustrates a top view of a standard compact work piece holdingvise;

FIG. 52 illustrates a side view of a standard compact work piece holdingvise;

FIG. 53 illustrates a front view of a standard compact work pieceholding vise;

FIG. 54 illustrates a top view of an embodiment of a motor mount vise;

FIG. 55 illustrates a side view of an embodiment of a motor mount vise;

FIG. 56 illustrates a side sectional view of an embodiment of a motormount vise;

FIG. 57 illustrates a front view of an embodiment of a motor mount vise;

FIG. 58 illustrates a sectional top view of an embodiment of thepositioning device with motor mount vises;

FIG. 59 illustrates a illustrates a sectional top view of an embodimentof the positioning device with motor mount vises;

FIG. 60 illustrates a sectional partial side view of an embodiment of amotor mount with vise locking;

FIG. 61 illustrates a partial front view of an upper portion of a rapidinstallation toggle-clamp mounting for removable, portable equipment;

FIG. 62 illustrates a illustrates a partial front view of a lowerportion of a rapid installation toggle-clamp mounting for removable,portable equipment;

FIG. 63 illustrates a side sectional view of a rapid toggle-clampmounting; and

FIG. 64 illustrates a partial side view of a lower portion of a rapidtoggle-clamp mounting.

DETAILED DESCRIPTION

The present invention is directed towards a robotic positioning device.With reference to FIGS. 1-3, a top view of an embodiment of the roboticpositioning device 101 is illustrated in FIG. 1, a front view of thepositioning device 101 is illustrated in FIG. 2 and a side view of thepositioning device 101 is illustrated in FIG. 3. The positioning device101 is mounted on a pan shaft 125 and can have a first payload 134and/or a second payload 136 rigidly coupled to opposite ends of a tiltshaft 105. The first payload 134 and the second payload 136 can bealmost any type of equipment including arms, cameras, lasers pointers,laser designators, laser range finders, laser power transceivers,spotlights, covert illumination, loud speakers, antennae, radar,sensors, less-lethal weapons, lethal weapons, and any combination ofsuch devices mounted together into a multi-sensor package. Thepositioning device 101 can rotate about the pan shaft 125 and the tiltshaft 105 can rotate within the positioning device 101 to rotate thepayloads 134 and 136. The positioning device 101 includes a housing 111and a top cover 113 that surround and protect internal electronics andmechanical systems that control the rotation of the positioning device101 and the tilt shaft 105. By transmitting control signals to themechanical systems, the first payload 134 and the second payload 136 canbe rotated into any angular position relative to the pan shaft 125 whichcan be stationary or movable.

FIGS. 5-9 and 11-16 illustrate embodiments of panning devices forrotatably moving a housing and attached or integral payloads about anazimuth. FIGS. 17 and 19-22 similarly illustrate embodiments of tiltingassemblies that can serve as a complete device for rotating attached orintegral payloads in elevation. These panning devices and tiltingdevices have break lines midway to better visualize their pairing intocomposite devices. The top of the housing is broken in each panningdevice embodiment, as is the bottom of each tilting device embodimenthousing, to better convey the modularity of pairing single-axis panningembodiments with single-axis tilting embodiments to create a combineddual-axis device capable of both panning and tilting of payloads. FIGS.10, 18 and 23-35 illustrate composites of various panning deviceembodiments combined with tilting device embodiments to effect dual-axispan-and-tilt positioning devices. FIGS. 36-46 illustrate embodiments ofa bearing common to all device embodiments. FIG. 47 illustrates adynamic rotary shaft seal. FIGS. 48-60 illustrate gear tracked andvise-locked adjustable motor mounts that can increase the shock andvibration tolerance of the positioning device and other belt, cable, andchain driven machines. FIGS. 61-64 illustrate a toggle-clamp mountingapparatus for rapidly installing and removing the positioning device orother portable devices from a mounting platform.

With reference to FIG. 5, a front cross sectional view of an embodimentof a panning device is shown. A housing 111 can rotate about fixed panshaft 125 to change the azimuth of payloads attached directly to, ormounted inside of, the housing 111. Housing 111 rotates about fixedshaft 125 via a pan bearing 127 which is shown in greater detail in FIG.41 and described in more detail later.

The positioning device can be mounted to the top of a pan shaft 125 witha pan bearing 127 coupled between a pan bearing flange 129 and arecessed, inner annular surface atop pan shaft 125. The pan bearing 127can include an inner ring 133, an outer ring 137 and a plurality ofbearings 135 between these rings that allow the outer ring 137 to rotatesmoothly around the inner ring 133. The pan bearing flange 129 can berigidly coupled to a lower portion of the housing 111 and the inner ring133 of the pan bearing 127. The outer ring 137 of the pan bearing can berigidly coupled to the top of the pan shaft 125. An outer ring 137 ofpan bearing 127 can have mounting holes with which fasteners rigidlyattach the outer ring to shaft 125.

To prevent damage to threads tapped into pan shaft 125, strong threadedinserts such as Keenserts or Helicoils can be embedded into the panshaft mounting hole pattern to greatly increase the thread strength. Thebearing inner ring 133 can also have mounting holes to attach thebearing to housing 111 via flange 129. In an embodiment, the pan bearingflange 129 can be rigidly coupled to the housing 111 and the inner ring133 of the pan bearing 127 with a plurality of screws, bolts or otherremovable fastening mechanisms. To prevent damage to threads tapped intothe floor posts of housing 111, strong threaded inserts such asKeenserts or Helicoils can be embedded into the housing to greatlyincrease the thread strength. The inner ring 133 can also be rigidlyattached directly to the lower portion of the housing 111 with aplurality of screws, bolts, or other fasteners as illustrated in FIGS.12 and 14, and the hole pattern in the housing floor can also bereinforced with threaded inserts. With reference to FIG. 12, planarsurfaces 168 of the outer ring can be very flat and the underside of panshaft flange 229 can be very flat and parallel; and the planar surfaces166 of the inner ring 133 can be very flat and parallel to an annularboss on the floor of the housing 211, the result of these flat andparallel joints being very concentric rotation of pan shaft 325 inrelation to bearing bore 167 and housing 211.

The pan bearing 127 assembly can allow the positioning device to rotateabout the pan shaft 325. The circumference of the outer ring 137 caninclude teeth which can engage a drive mechanism which will be describedin more detail. The teeth profile can be hobbed directly onto thecircumference of outer ring 137, directly into the circumference of panshaft 125 as illustrated in FIG. 5, or a ring of pulley stock can berigidly attached around the outer ring 137 or around pan shaft 125 tocreate an integrated shaft gear. In an embodiment, the tooth profile ishobbed directly into shaft 125, with belt 106 mating with the gear teethto apply torque to the shaft 125 and thereby create rotary motion. Theinner surface of the pan belt 106 and the outer surface of the outerring 137 can have corresponding teeth to prevent slipping, called‘ratcheting’ when the belt is synchronous, between the pan belt 106 andthe outer ring 137. By precisely controlling the movement of the panningdrive mechanism, the housing 111 can be accurately rotated to anydesired azimuth position.

With reference to FIG. 23, an internal power supply 118 can provideelectrical power to control electronics and motor components. Power andcontrol signals can enter into the positioning device via connector 141and interface to electronics enclosed in the wide space within pan shaft125, and these power and data signals can be routed further up intohousing 111 by passing through the thru-bore 167 of pan bearing 127. Toprevent shaft rotation from excessively flexing wires or yanking wiresfree of their receptacles, a slip ring 140 can be placed in bore 167,rigidly mounted to the fixed shaft 125 by slip ring bracket 180. Thecomponents enclosed in shaft 125 and housing 111 can be protected fromthe environment by a dynamic shaft seal 152, as well as static sealsaround any penetrations and between faying edges of the housing 111.Both air valve 150 and connector 141 can have static seals to preventleakage where they penetrate the exterior walls, and air valve 150 canpurge and pressurize the sealed housing 111 with clean, contaminant freegas.

With reference to FIG. 6, the pan belt 106 meshes with a belt profilecut directly into the circumference of outer bearing ring 137 to createa geared bearing, as illustrated in FIGS. 37-39, or a separate ring ofhobbed pulley stock can be press-fit or otherwise rigidly attachedaround outer ring 137 of un-geared bearings such as those illustrated inFIGS. 40 and 41 to similarly effect a geared bearing. The inner surfaceof the pan belt 106 and the outer surface of the outer ring 137 can havecorresponding teeth to prevent slipping between the pan belt 106 and theouter ring 137. Horizontal break lines through FIG. 6 illustrate threedifferent top-down views in FIGS. 7-9, with FIG. 9 showing the view fromwhich the sectional of FIG. 6 is illustrated. With reference to FIG. 7,a top view of housing 111 orients a front side 122 at the bottom of theview, with a rear side 124 of the panning device at the top of the view.Eight sectioned posts in the floor of housing 111 illustrate how panbearing flange 129 can bolt into the housing. Pan shaft 125 penetrateshousing 111 from beneath and can have a pattern of bolt holes 395 forfastening the outer ring 137 of pan bearing 127. Alignment pins 138pressed into precisely located holes 396 can precisely seat the outerring 137 atop pan shaft 125 to precisely align the shaft through thecenter of the bore in the housing floor. Slip ring 140 can be fixed toshaft 125 by slip ring bracket 180 which can rigidly attach to a shelfinside shaft 125, or the flange of slip ring 140 can fasten directlyinto this shelf. Moving up in elevation to the view in FIG. 8, pan shaftgear outer ring 137 is mounted atop pan shaft 125. A similar top planview of the bearing is illustrated in FIG. 36, showing each ring canhave a multitude of various mounting holes 395, alignment pin holes 396,a central bore 167, and bearing seals 160. With reference to FIG. 9, apan bearing flange 129 rigidly attaches to pan gear inner ring 133, andcan have alignment pins 138 to precisely seat the pan gear 127 onto thepan bearing flange 129. Cutouts in the flange permit tool access to thefasteners in mounting holes 395 and alignment pins 138 in alignmentholes 396; manually rotating the shaft 125 can position each fastenerand pin below an access cutout. These cutouts also provide access forinstalling and tensioning belt 106. A second motor gear 104 having anaxis of rotation parallel to the axis of rotation of the shaft gear 127can be driven by a motor to transfer torque to shaft 125 via a directmeshing of their gear teeth or via a belt 106 as illustrated. A panmotor 102 (out of view) above pan gear 104 can be rigidly coupled to thehousing 111. The rotor of pan motor 102 rotates when electrical power isapplied which rotates the pan gear 104 and moves the pan belt 106 whichcauses the outer ring 137 to rotate relative to the inner ring 133coupled to the housing 111. Because the pan motor 102 is fixed inrelation to the housing 111, the movement of the pan motor 102 causesthe housing 111 to rotate about the pan shaft 125. By controlling themovement of the pan motor 102, the positioning device 101 and the firstpayload 134 and second payload 136 (viewable in FIGS. 1-4) can beaccurately rotated to any desired rotational position. The broken viewline depicts the datum and orientation from which the sectional of FIG.6 is taken.

With reference to FIG. 10, pan bearing flange 129 has been integratedwith housing 111. A pan motor gear 104 can be driven from a pan motor102 mounted to pan motor bracket 282 which sits atop rails integral withthe floor of housing 111. In the illustrated embodiment, the bracket 282and the pan motor assembly are independent structures from pan bearingflange 129, unlike the embodiment illustrated in FIG. 9 where the panmotor bracket 282 (motor bracket not visible in FIG. 9) mounts atop panflange 129. By separating the motor mounting features from the pan shaftgear mounting features, there is more flexibility in the manufacturingassembly stage to optimize the procedure for mounting parts in thesetight spaces. The separation between the integral shaft flange 129 andbracket 282 creates additional working space to install and tension belt106. Towards housing rear side 124, tilt motor bracket 115 has mounted asecond motor 112 and motor gear 114 to the integral flange insidehousing 111 to introduce the beginning of a 2-axis embodiment. Tiltmotor 112 is suspended above a cutout in the integral flange of housing111, below which are threaded posts or threaded inserts to mountelectronics or other accessories to the floor of housing 111. Withreference to FIG. 59 is a plan view of a similar embodiment with anintegral pan bearing flange 129 and separate motor mount plates 282 and115, but wedges 670 are driven by screws 671 to slowly and incrementallyposition and hold the motor mount plates for proper belt tension. FIG.60 illustrates a sectional partial side view of the tilt motor assemblyof FIG. 59, whereby wedge 670 presses tilt motor bracket 115 radiallyaway from the tilt axis by turing screw 671. With reference to FIG. 48is a front sectional view of a pan motor embodiment that could be pairedwith the housings of FIGS. 10 and 59, but with a linear gear belttensioning system instead of a wedge. The necessity of the geared andwedged motor mounts in a precision drive will be discussed in greaterdetail.

With reference to FIG. 11, a pan-thru shaft 425 is rigidly attached topan shaft 125. A full dual-axis pan-thru shaft device embodiment isillustrated in FIGS. 34 and 35, permitting a payload to be mounted freeof any motion of the pan and tilt action. FIGS. 12-16 illustrateadditional embodiments of panning devices. With reference to FIG. 12,pan shaft gear 127 attaches directly to the floor of housing 211 insteadof through the pan bearing flange 129 of previously discussedembodiments. Pan shaft 325 must be narrower than pan shaft 125 henceillustrated in order to pass through the pan shaft gear bore 167. Thebore in the floor of housing 211 can be narrower than housing 111, asnarrow as pan gear bore 167, which may permit a smaller dynamic shaftseal 52 and smaller housing 211. Pan shaft 325 installs from belowhousing 111, and a pan shaft flange 229 rigidly couples the geared outerring 137 to shaft 325. With reference to FIG. 14, pan gear 127 alsobolts inner ring 133 directly into the floor of housing 211, but panshaft 225 installs from the top to permit a strong integral pan shaftflange 229 rather than the separately attached pan shaft flange 229 ofFIG. 12. The base of pan shaft 225 can have integral threads or threadedinserts such as Keenserts or Helicoils for attachment to a base, or abase plate adapter 291 can attach to widen the base of the pan shaft 225which was forcibly narrowed by design to pass through pan gear bore 167.Dynamic shaft seal 152 requires a restricted opening to be shielded fromdirect debris and air blast impacts, so removable seal gland shield 155can be attached to the underside of housing 211. View lines 15 and 16depict top-down views of FIG. 14 in the same manner as FIG. 6 referencedtop-down views in FIGS. 7-10. With reference to FIG. 15, an annular bossin the floor of housing 211 includes a bolting circle with bolts 465mounting inner ring 133, and can include alignment pin holes foralignment pins 138 to precisely locate the inner ring 133 of pan gear127. With the pan gear installed, pan shaft 225 installs by penetratingthrough the hole in the floor of housing 211, dropping down from above,with slip ring 140 enclosed in the hollow pan shaft 225. With referenceto FIG. 16, the top of pan shaft 225 includes an integral flange thatfastens into pan gear outer ring 137 (shown in FIG. 14), and can includealignment pins 138 to precisely position the pan shaft inside the narrowbore in housing 211. Pan motor mount 182 attaches to the floor and wallsof housing 211 to mount the motor 102 independently of the pan shaftflange 225, as similarly illustrated in FIG. 10. Tilt motor supportplate 183 is also independent of pan shaft 225 to afford flexibility inthe assembly process. The break line shown in FIG. 16 illustrates FIG.14 as a bisected front sectional viewed from front side 222 toward rearside 224, with FIGS. 15-16 being above plan views thereof.

Each embodiment illustrated thus far has detailed methods for mountingthe inner ring of a turntable bearing or slew ring to a housing whilethe shaft is mounted to the outer ring. With reference to FIG. 13, theopposite ring mounting method is illustrated with pan bearing outer ring137 fastening directly into the floor of housing 211 while inner ring133 is rigidly mounted to the flange of pan shaft 225. Outer ring 137 isfixed and thus cannot serve as a gear, so the flange of pan shaft 225must have a belt profile hobbed directly into an accessible pulleydiameter, or a hobbed ring can be press-fit or otherwise attached aroundthe edges of the pan shaft flange 229 to permit a pan belt 106 to applytorque necessary to rotate the shaft. For a vertically compactedassembly, the flange of pan shaft 225 can arch over the pan bearing 127and overhang outer ring 137 with a geared pulley surface on thecircumference of the overhang. This embodiment enjoys the added loadhandling capacity and removability afforded by the turntablebearing—which alone is a significant advantage if reports of rampantbearing destruction in prior art is to be relied upon—, but may not beas cost effective as the geared bearing embodiments, the narrow panshaft may lack the tubular rigidity of the wide pan shaft embodiments,and the belt may not be as aligned between the motor and shaft gears aswith the geared bearing.

FIGS. 5-16 have illustrated various embodiments of a shaft which rotateswith respect to a chassis or housing via a mounting-holed turntablebearing instead of pairs of press-fit bearings typical of prior art. Theouter ring 137 can be mounted to the shaft, with the inner ring 133mounted to the housing, or vice-versa, and the shaft can be designed toinstall into the housing from either direction. The design choices onwhich ring to mount to which surface, and which end to insert the shaftfrom lead to a variety of embodiments; however, selection of aparticular embodiment is not arbitrary. Each configuration has costs andbenefits in physical strength, rigidity, vibration resistance,complexity, cost, and ease of assembly and repair; characteristics whichwill be disclosed in more detail once the figures have each beendescribed.

FIGS. 17 and 19-22 illustrate tilting positioning devices in a similarmanner as to how the panning device embodiments where presented by FIGS.5-16. The tilting devices can utilize the same type of turntable bearingand thus have components and mounting permutations very similar to thosefor the azimuth panning devices, though shifted to an orthogonalorientation.

With reference to FIG. 17, an elevation, or tilting, positioning devicecan include a drive mechanism for rotating the tilt shaft 105 within thehousing 111. A tilt shaft 105 penetrates two sides of housing 111; thetilt shaft 105 can extend through the housing 111 and exit the housing111 through a first side 121 and a second side 123. Performing the samefunction of pan bearing flange 129, a tilt shaft flange 241 rigidlycouples the inner ring 133 of a tilt shaft gear 131 to the wall 121 ofhousing 111. Tilt shaft gear 131 can be coupled between an inner ring133, an outer ring 137 and a plurality of bearings 135 between the innerring 133 and the outer ring 137 that allow the outer ring 137 to rotatesmoothly around the inner ring 133. A tilt shaft flange 107 can berigidly coupled to one side of the tilt shaft 105 proximate the firstside 121 of the housing 111. The tilt shaft flange 107 can be rigidlycoupled to the outer ring 137 and the inner ring 133 can be rigidlycoupled to a second tilt shaft flange 241 rigidly coupled to the firstside 121 of the housing 111. The inner ring 133 can have a plurality ofthreaded mounting holes and the flange 241 can have correspondingthru-holes in the same pattern. Bolts 465 or other removable fastenerscan be placed through the mounting holes in the flange 241 and tightlyscrewed into the threaded holes in inner ring 133. The tilt shaft flange107 can have a plurality of threaded mounting holes and the outer ring137 of the tilt bearing 131 can have corresponding thru-holes. Bolts 465can be placed in the mounting holes in the outer ring 137 and tightlyscrewed into the threaded holes in the tilt shaft flange 107. Thesethreaded holes in tilt shaft 107 can be reinforced with threaded insertssuch as Keenserts or Helicoils. As with all threaded fasteners in thepositioning device, threadlocking compound can be applied to fastenersto reduce vibration induced loosening. Outer ring 137 mounts to the tiltshaft flange 107. The circumference of outer ring 137 can include teeththat can engage a drive mechanism which can be a belt, another gear, orother actuator that is coupled to a tilt motor which will be describedin more detail.

With reference to FIG. 18, the tilt motor 112 and tilt motor gear 114can be rigidly coupled to the housing 111. The rotor of tilt motor 112rotates when electrical power is applied which rotates the tilt gear 114and moves the tilt belt 116 which causes the outer ring 137 of tiltshaft gear 131 to rotate relative to the inner ring 133 coupled to thehousing 111. Because the tilt motor 112 is fixed to the housing 111, themovement of the tilt motor 112 causes the tilt shaft 105 to rotatewithin the housing 111, with payloads 134 and 136 (shown in FIGS. 1-4)tilting in elevation with respect to the housing 111. By controlling themovement of the tilt motor 112 and attached drive mechanism, the firstpayload 134 and second payload 136 can be accurately rotated to anydesired angle of elevation.

To relate the tilt shaft to the described panning devices, rotate thepage illustrating FIG. 6 by 90° clockwise and compare this view to FIG.17. A flange 129 in FIG. 6 attaches the inner ring 133 of the pan shaftgear 127 to the housing 111. In the same manner, a flange 241 in FIG. 17attaches tilt shaft gear 131 to the housing 111 via inner ring 133. Forboth embodiments, the outer ring 137 is attached to their respectiveshaft, but tilt shaft 105 in FIG. 17 steps-down the diameter of theshaft to the left of the gear mounting surface, creating a flange 107,whereas pan shaft 125 of FIG. 6 maintains a large shaft diameter. Byconstricting the tilt shaft 105 in FIG. 17, the bore in the side of thehousing side 121 can be reduced, along with shaft seal 152 and sealshield 155. Size and weight of tilt shaft 105 are reduced by steppingdown the diameter of the shaft to the left of the mounting surface onflange 107. The left end of tilt shaft 105 can mount to a payloadinstead of a base, so it may not require the tubular rigidity affordedby the wide pan shaft 125. By varying the shaft diameter, a deviceembodiment can be tailored for size, weight, rigidity, andshaft-to-payload interfacing geometry. Further performance metrics canbe optimized with consideration as to how the shafts are installed intothe housing 111.

With reference to FIGS. 17-23, the tilt shaft 105 penetrates two wallsof a unibody structure and is broken into two pieces to permitinstallation of a shaft piece with an integral shaft flange 107, whichmay be stronger than a separately attached shaft flange. The left sideof tilt shaft 105 installs from the inside and penetrates out side 121of housing 111. The right side of tilt shaft 105 can be a wide, steppedshaft similar to pan shaft 125, and must insert from the exterior,entering through wall side 123. With reference to FIG. 18, a top-downview illustrates the compact device may not have much wasted internalspace, so selections of shaft pieces and their mounting procedure mustconsider what is physically possible for the technician to perform, notjust optimizing size, weight, and rigidity for performance.

With reference to FIGS. 1-4, the purpose of tilt shaft 105 can be torotate payloads to a desired angle of elevation. A first payload 134 canbe attached to one end of the tilt shaft 105 and a second payload 136can be attached to the opposite end of the tilt shaft 105. The payload134 has been omitted from most other figures to dedicate the page areato illustrating the moving parts. A shaft end cap can be bolted onto anend of tilt shaft 105 to seal and protect the shaft end if only onepayload is desired.

A payload can be integral with the housing 111. Thus, the payload andthe housing 111 can be coupled and rotate together in azimuth relativeto the pan shaft 125. With reference to FIG. 29, cover 113 can beexpanded upward to expand the hollow volume within housing 211 enough tofit a payload device.

With reference to FIG. 19, bearing mounting bosses on the interior ofsides 121 and 123 are undercuts with precision bores that may bedifficult and costly to mill into metal stock, though these features maynot be an issue for cast or molded construction such as cast metal,injection molded engineering plastic, or graphite fiber composite. Inembodiments where the housing walls 121 and 123 do not have an outwarddraft, or are otherwise crowded inside, integral shaft mounts may beobstructions to assembly and disassembly. With reference to FIG. 22, aremovable circular bracket 128 can be placed around the tilt shaft 105between the inner ring 133 of the tilt bearing 131 and the first side121 of the housing 111. The inner ring 133 fasteners can extend throughholes in the bracket 128 and can be threaded into tapped holes orthreaded inserts in the first side 121 of the housing 111. The bracket128 can include a bore that houses the dynamic seal 152. A secondremovable tilt shaft bracket 145 can mount a radial bearing 144 againstwall side 213. The radial bearing outer race can be tightly press-fitinto a precision bore in bracket 145, and can have a loose press-fitbetween the inner race of bearing 144 and the shaft 105. While tiltbearing 131 has considerable load capacity, bearing 144 can complementthe load capacity of tilt bearing 131 as a safety factor. Fasteners canextend through holes in the bracket 145 and can be threaded into tappedholes or threaded inserts in the second side 123 of the housing 111.Both brackets 128 and 145 can have precision alignment pins 138 to alignthe bearings 131 and 144 which will reduce unintended preloading due toshaft misalignment. Molded construction may have challenges or costsassociated with the tolerances and surface finishes of the bores in thehousing walls and floor, as well as tolerances for the bearing mountingholes and precision bearing alignment pins 138, so brackets 128 and 145can be solid inserts permanently embedded into the walls during themolding process.

With reference to FIG. 19, the turntable bearing 131 may sufficientlyhandle loads as the sole bearing on the shaft when equipped with highcombined load capacity of 4-point contact races, duplex angular bearingelements, or roller bearing geometry as illustrated in FIGS. 42-46. Withreference to FIG. 42, illustrated is a close-up view of the rollingbearing elements of an embodiment of a turntable bearing. Ball bearings135 roll between grooves 393 in the edges of the rings 133 and 137.These grooves can be gothic arch raceways that contact the balls 135 atfour points 399. A lubricant can fill the balls and raceways to reducefriction, dissipate heat, and prevent corrosion; this lubricant can beelectrically conductive to reduce arcing across the balls and lowerimpedance between the rings 133 and 137 to better effect a Faraday cage.The bearing can include a separator ring 162 to separate the balls.Notches 397 can be cut into the rings to retain face seals forprotection from contaminants. With reference to FIG. 43, two rows ofballs are stacked to increase load capacity. This is a back-to-backduplex angular bearing with each ball contacting two points 399. Innerring 133 must be split into two pieces 233 to assemble, while outer ring137 can remain a thick, single ring capable of accepting an externalgear profile. Face seals 160 can be supported with rigid shields 161. Toreduce weight, balls 235 can be silicon nitride. Instead of a separatorring 162, silicon nitride balls 235 can be alternated with slightlysmaller steel spacer balls 135; however, silicon nitride rollers havereduced load capacity for impact loads and are not electricallyconductive. With reference to FIG. 44, balls 135 can contact races atpoints 399 in a face-to-face duplex angular orientation. A pair ofseparator rings 162 can space the balls 135. Split inner ring 233 can befastened together to assemble and pre-load the bearing, or otherpresser-flanges can be used. With reference to FIG. 45, a single row ofcylindrical roller bearings 335 can be used instead of balls. Therollers can be at an angle to handle a combination of loads. Withreference to FIG. 46, three rows of cylindrical rollers 335 can becombined to form a triple row crossed-roller bearing with very highrigidity and load capacity for large and heavy embodiments of thepositioning device 101. The outer ring 237 can be split to enableassembly.

To increase load capacity of the titling shaft assembly withoutupgrading the 4-point angular contact turntable bearing 131 to a largerduplex angular or roller bearing, a second bearing 144 can be rigidlymounted on side 123 to limit the moment and radial loads seen by thetilt bearing 131. With reference to FIG. 20, a bushing or bearing 144can be placed between the tilt shaft 105 and the second side 123 of thehousing 111. This configuration allows the tilt shaft 105 to rotatesmoothly relative to the housing. Bearing 144 can be a radial bearingwhich has a loose fit or light press-fit around tilt shaft 105 such thataxial loads and some moment loads are delegated to the more capableturntable bearing 131. This bearing can be press-fit from the exterioras well as from the interior. With reference to FIG. 21, this radialbearing can be a removable flange-mounted bearing 143 instead ofpermanently press-fit bearing 144. With reference to FIG. 22, radialbearing 144 is press-fit into a bracket 145. This bearing assembly canbe removed and discarded if the bearing fails, it eliminates expensiveor impossible undercuts associated with milling the housing 111, and itmay be necessary in assembly procedures which otherwise would beobstructed by the shaft mounts 128 and 145 illustrated in FIG. 22. Withreference to FIG. 21, tilt gear 131 can also be mounted from theexterior, with bolts penetrating housing 111 side 121 from the exterior.

With reference to FIG. 17, tilting shafts of the tilt positionersdescribed can also include a slip ring 140 or a similar thru-bore slipring, and these implementations can be predicted from the panningdevices. A shaft penetrating both walls must protect wire harnessesrouting between the payloads 134 and 136 and interior of the housing111. The range of motion for the shaft must be limited to prevent wiresfrom flexing to a critical bend radius or being yanked out of theirreceptacles. To limit the range of motion of the tilt shaft, tilt shaftmounting flange 241 can have a keyed bore. Lower side 728 can have awide bore while upper side 628 can have a thick wedge or key. Theadjacent shaft diameter of tilt shaft 105 can have a correspondingmating shape whereby upper side 190 can have a small diameter whilelower side 191 can have a wide diameter or key. Bore 728 and shaftdiameter 190 can provide clearance for rotation until the protrudingkeys of 628 and 191 rotate into each other to physically obstructfurther motion. Other embodiments can use alternative obstructions. Withreference to FIG. 22, tilt shaft flange 107 includes a rod-likemechanical stop 108. Under normal range of motion, the protrusion 108can glide above the top of shaft mount bracket 128. The opposite end ofthe bracket is raised and shaft stop 108 is too long to pass over theraised key. The position of the stop 108 can coincide with the shallowand raised areas of bracket 128 to pass or obstruct motion within adefined angular range of rotation. With reference to FIG. 19, theunderside of housing cover 113 can have a protrusion 109. One or twotilt shaft flange stops 108 can protrude inward, opposite the directionfrom FIG. 22, but are hidden behind tilt shaft 105 in this view. Theprotrusion 108 can impact the cover stop 109 to prevent excessiverotation. These three disclosed methods provide for a range of motionless than 360 degrees, though a more complex floating mechanical stopcan permit wider ranges such as 540 degrees or even adjustable hardstops.

To sense the angular position before the mechanical stops crash intoeach other, a position sensor 146 mounted to side 123 can read featuresin flange 147 rigidly attached to tilt shaft 146. Sensor 146 can be amagnetic sensor or Reed switch sensing magnets attached to flange 147,and the magnets can be patterned to permit an incremental or absoluteencoding of the shaft orientation. Sensor 146 can also be an opticaldevice which passes or reflects a beam off of the flange to detect areferenced position. The flange 147 can also be patterned such that theread head 146 output is an optically encoded incremental or absoluteposition. Flange 147 can be keyed with tilt shaft 105 to preciselyangularly align the flange features with the read head point ofreference. Tilt shaft 105 can attain a highly consistent angularalignment and accurate position reading for the read head 146 byutilizing keyways and alignment pins 138 at each linkage. With referenceto FIG. 36, each turntable bearing ring can have at least two precisionalignment holes 396. With reference to FIG. 23, wall side 121 can haveprecisely located alignment pin holes with alignment pins 138 (notshown) that align with the precision alignment holes 396 of the innerring 133 of tilt gear 131. Tilt shaft flange 107 can also use alignmentpins or holes that engage alignment pins or holes in outer ring 137 toprecisely locate the outer ring and tilt shaft. With precision alignmentbetween the tilt shaft bearings 131 and 144, the rotation of tilt shaft105 can be very smooth and concentric, and may not grind in the tightbores where they pass through the housing walls. To correct furtheralignment errors and imprecision in the bearings and shaft, a shaftcoupler 188 can compensate shaft misalignment, and can include a flange147 for position sensing. The pan shaft can similarly achieve an angularposition reading by mounting a read head to the housing, such as atoppan bearing flange 129, with an encoder wheel mounted to slip ringbracket 180 or atop the flange of slip ring 140. In an embodiment, theturntable bearing 131 has alignment pin holes and pins inserted into thepin holes to precisely locate each ring into the housing wall and tiltshaft flange 107. To precisely and repeatably aim payloads, precisionalignment pins 138, keyways, and a shaft coupler can keep shaftcomponents very aligned to each other; mechanical stops can be used tolimit rotation and calibrate position; while sensors can be used tocalibrate and read the angular position.

The tilting device embodiments must protect the drive components andsensitive electronics from the environment. With reference to FIG. 17,cover 113 can be attached to the top of the housing 111 with a pluralityof screws, bolts or other fasteners. A corresponding mounting holepattern in the mating flange of housing 111 can embed threaded insertsto improve thread strength. A groove in this top flange of housing 111can have a static seal 156 to prevent leakage past the faying edges ofthe cover and housing 111. An overbite-type ledge a.k.a. a ‘torturouspath’ on the cover inhibits light, water jets and electrical threatsfrom reaching the seal 156 directly. In an embodiment, a dynamic rotaryshaft seal (‘dynamic seal’) 152 can be placed between the tilt shaft 105and the inner ring 133 of the tilt bearing 131. This dynamic seal 152allows the shaft to rotate without breaking an air-tight seal. The rightside of tilt shaft 105 also can also have a dynamic seal for acomprehensive sealing solution. With reference to FIG. 47, seal 152 caninclude a spring 252 to maintain contact under erratic shaftoscillations, high impulses of fluid pressure such as concussive blasts,and the spring can maintain contact if minor shaft misalignment isapplying non-uniform pressure. The right side of seal 152 is called theheel, and it can be extended in length for additional rigidity underpressure. Under high external pressures, the base of the heel mayextrude between the narrow bore of housing 111 and tilt shaft 105, knownas the extrusion gap, which pulls the seal out of alignment with theshaft. An extended heel limits some extrusion, while a harder materialco-extrusion 352 can be included to further prevent the seal fromextruding through the extrusion gap. Dynamic seals are often delicate sothe ends of shaft 105 can be chamfered or rounded, as are the ends ofshafts 125, 225, 325, and 425 in all embodiments, to avoid gouging theseal 152 surface. With reference to FIG. 21, the bolt heads and holes onside 121 are sources of leakage from the environment and thus require anoutboard seal, even when the bolts include individual seals, but theshaft seal 152 cannot seal properly against the tops of the fastenersand counterbores in this wall. Bracket 154 can effect a proper sealgland for dynamic shaft seal 152, and a backup static seal 156 canprevent contaminants from bypassing the dynamic seal 152. A seal glandshield 155 attaches to the exterior of wall 121 to restrict gas pressurewaves and jets of contaminants from entering the seal gland, yet theopening remains wide enough to let trapped water and debris escape. Withreference to FIG. 22, the shaft seals have been integrated into tiltshaft mount brackets 128 and 145 inside the housing 111. To preventcontaminants leaking past the seal, each bracket can include a backupstatic seal 156. With reference to FIG. 5, an air valve 150 can beincluded to purge and pressurize any enclosed, sealed device embodimentor payload.

With reference to FIG. 22, conditioned electrical power can be providedby power supply 118 attached to wall side 123, visible behind the tiltshaft 105. Also visible behind the tilt shaft is tilt motor 112. Thismotor attaches to adjustable tilt motor bracket 115 which fastens intothe housing 111 via pan bearing flange 129. With reference to FIG. 18,an above plan view of an embodiment is illustrated, with the housingcover 113 omitted for clarity. FIG. 18 is similar to the panning deviceof FIG. 9, but includes the tilt shaft 105 drive mechanism whichincludes a tilt motor 112, a tilt gear 114 and a tilt belt 116. The tiltmotor 112 is coupled to the housing 111 and positioned between a fourthside 124 of the housing and the tilt shaft 105. The tilt gear 114 iscoupled to the tilt motor 112 and drives the tilt belt 116 thatsurrounds the outer ring 137 of the tilt bearing 131. The tilt motor 112and pan motor 102 can be mounted on the opposite sides of the tilt shaft105 within the housing 111 which can result in a positioning device thathas a balanced weight distribution of components. Tilt motor 112 isrigidly mounted to tilt motor bracket 115, said bracket equipped withslots to tension the tilt belt 116 through a range of adjustment. Inanother embodiment discussed later, the tilt motor is attached andtensioned with a ratcheting mechanism which is less likely to breakloose under vibration and shock than bracket 115. Once the belt istensioned, tilt motor bracket 115 is fastened into position atop panbearing flange 129 or similar structure rigidly attached to the housing.Tilt motor 112 has a tilt motor gear 114 attached to its rotor shaft,with tilt belt 116 wrapped around tilt motor gear 114 and tilt shaftgear 131. The inner surface of the tilt belt 116 and the outer surfacesof the outer ring 137 and tilt motor gear 114 can have correspondingteeth to prevent slipping between the tilt belt 116, the outer ring 137and outer surface of tilt motor gear 114. When the motor is actuated,the tilt motor gear 114 drives the tilt belt 116, which rotates theouter ring 137, which rotates tilt shaft 105 via tilt shaft flange 107.To prevent the belt from walking off the gears, shaft gears 127, 131 andmotor gears 114 and 104 can include flanges to retain the belt 116.Alternatively, with reference to FIG. 23, abutting features to the gearscan serve as flanges; for example, tilt shaft flange 107 can have aslightly larger diameter than tilt shaft gear 131 to serve as aretaining flange from the belt 116 walking inward, while the interiorwall side 121 can be close to the tilt shaft gear 131 to prevent thebelt 116 from walking outward. Similarly, pan belt 106 can be retainedby the top of pan shaft 125 being slightly larger than the diameter ofpan shaft gear 127, while the underside of pan bearing flange 129 canserve as a low roof to block the belt 106 from walking upward. Belts 116and 106 can also be belts with peaked teeth that tend to center thebelt, and the belts can include tensile members woven in a pattern thatresists walking off center.

FIG. 23 illustrates a front sectional of a complete 2-axis pan-tiltpositioning device with the section plane slicing through the centers ofthe pan and tilt axes. Having comprehended various embodiments ofsingle-axis panning-only devices and tilting-only devices, this dualaxis device 101 can be understood as a composite of the panning deviceof FIG. 6 and the tilting device of FIG. 19. Broken view lines directtowards various top-down plan views in FIGS. 24-28; the broken linesroute through the drawing in indirect paths to isolate features ofinterest instead of taking horizontal sectional slices. Unlike the truetop sectional views of FIGS. 7-19 and 15-16, the top-down plan views ofFIG. 24-28 are not sectionals and have no sectional hatching, rathercomponents above the horizontal broken view lines in FIG. 23 havegenerally been removed from consideration to avoid distraction from thefeatures most germane to the invention claims.

With reference to FIG. 24, illustrated is a partially assembled device101. An un-sectioned housing 111 is seen from above, with the cover 113omitted from view to expose all of the interior components; thesefigures are meant to depict what an assembly technician would see atvarious stages of fabricating the device 101. Only main housing 111 isin view, with features of the floor exposed. Unlike the sectioned topviews of FIGS. 7-10, we can see that the tilt bearings 131 and 144mounting bosses on the wall sides 121 and 123 could provide obstructionsfor assembly when housing 111 is dimensioned as small as possible tocreate a compact positioning device. The top of housing 111 has a largeflange with a groove filled with static seal 156, and many threadedholes outside of the seal groove permit the cover 113 to attach with aconsistent, even, high pressure to maintain a tight environmental sealand low-impedance electrical shield bond.

In FIG. 25, a view of the same embodiment of FIG. 24 but taken slightlyhigher in elevation, is an un-sectioned view of FIG. 8 which illustratesa device partially assembled to afford clarity not conveyed by thesectional drawing of FIG. 8. The pan gear 127 sits atop pan shaft 125,with slip ring 140 supported by slip ring bracket 180. Around theperimeter are eight threaded posts for pan bearing flange 129 to fasteninto the housing 111.

With reference to FIG. 26, an un-sectioned view of a device further inassembly reveals the cutouts in pan bearing flange 129 are required toclear the tilt shaft bearing mounts as well as to provide access to thefasteners and alignment pins 138 of outer ring 137. Pan bearing flange129 is visible as a rigid member anchoring the pan shaft assembly to themain enclosure structure 111. Cutouts in the pan bearing flange 129 canbe used to access the bolt pattern of pan turntable bearing outer ring137, provide access to install and adjust pan belt 106, and reduceweight of the flange.

With reference to FIG. 27, the pan motor 102 is installed, along withpower supply 118. With reference to FIG. 28, a view of device 101 isillustrated, fully assembled except for the housing cover 113. Tiltshaft 105 is orthogonally positioned above pan shaft 105 to reducemoment loads that reduce the efficiency of motion, such inefficienciesreducing the maximum permissible weight of payloads and speed they canbe rotated. A tilt shaft mechanical stop 108 is now visible, where ithad been obscured behind tilt shaft 105 in front sectional views. A newcomponent is introduced in this view, central electronics controller574, which can be an embedded processing platform for controlling themotors; controlling the payload devices; processing and encoding sensordata such as video; monitoring position sensors; actuating the motors tocounteract sensed motion in the base to actively stabilize the payloads;monitoring the power supply 118; monitoring internal environmentalsensors such as humidity, temperature, and gas pressure; processingcommands from the user(s) generated by HID 575 or an external controller573 as illustrated in FIG. 4; operating the device autonomously with anonboard AI; or performing any other task common among embeddedcomputers. Controller 574 is mounted to the housing 111 by internalcontroller bracket 173. A thermal pad or compound between a side ofcontroller 574 and bracket 173 can conduct electronics generated heatinto bracket 173, heat which then conducts into the walls of housing111. Heat pipes can be attached between high heat generating componentson the controller and the housing 111 or cover 113 for more direct andefficient dissipation of generated heat. The external surfaces ofhousing 111 and 113 can have fins or pins to dissipate the heat into theair.

With reference to FIG. 29, another 2-axis positioning device 201 isillustrated. This device can be comprehended as a composite of thepanning device of FIG. 14, with the tilting device of FIG. 20. Withreference to FIG. 30, a third dual-axis embodiment is produced by thecombination of the pan device of FIG. 14 with the tilting device of FIG.22. FIG. 30 is elaborated through top-down plan views in FIGS. 31-33.Because the upper components block view of components and importantfeatures buried deeper within, FIGS. 31-33 have been provided to focusattention to features at various depths within the complete positioningdevice. A horizontal broken line along the tilting axis 105 in FIG. 33denotes the section plane for the view of FIG. 29. With reference toFIG. 31, housing 311 is shown; it does not include integral tilt shaftmounts, rather the walls can be vertically straight. With reference toFIG. 30, Pan bearing 127 installs from above, its inner ring 133 boltinginto an annular boss around the bore in the bottom of housing 311, alsovisible in FIG. 31. Tilt shaft 225 is inserted from above, its flange229 bolting into outer ring 137. With reference to FIG. 32, a pan belt106 can be wrapped around the outer ring 137 of pan shaft gear 127. Apan motor support plate 182 can rigidly attach to the housing 311 tocreate a level platform to mount pan motor 102 and an adjustable motormount, and a second platform 183 can be mounted to the housing 311 toaffix the tilt motor via tilt motor bracket 115. Motor support plates182 and 183 can have cutouts for access to wrap pan belt 106 around thepan motor gear 104, and minimize weight. With reference to FIG. 33, acomplete top view of device 301 is illustrated, except for housing cover113.

With reference to FIG. 34, a dual-axis positioning device 401 with apan-thru shaft is illustrated. Because pan shaft 125 is now extendedthrough the roof 413, the tilt shaft 105 must be shifted off the panaxis for clearance. The pan-thru shaft can be a single shaft or a secondshaft 425 that rigidly attaches to pan shaft 125, or passes through thecenter of pan shaft 125 to bolt directly into the mounting base. As withthe tilt shaft assemblies, a second bearing 144 can be used on the roofopposite the pan shaft gear 127 to constraint eccentric motion, radialloads, and moment loads that could damage the bearings of pan shaft gear127. As illustrated in the tilt shaft of FIG. 23, but not in this view,a shaft coupler 188 can interface pan shaft pieces 125 and 425. Becausethe tilt assembly is shifted behind the datum of view, the tilt motorsubassembly comes into view. Tilt motor 112 and its tilt motor gear 114can engage tilt belt 116 to rotate tilt shaft gear 131. Atop pan-thrushaft 425 is mounted fixed payload device 434. Fixed devices arecommonly radars, antennae, or fixed wide-angle cameras that do notrotate. Because the main housing cover 413 rotates about the fixed shaft425, a dynamic shaft seal 152 is included in the underside of payloadhousing 434, oriented downward to prevent ingress of rain or other fluidthat may pool or splash atop cover 413. A pan-thru shaft flange 429rigidly attaches the payload 434 to the pan-thru shaft 425, andalignment pins or a keyway can be used to tightly align the azimuth ofthe payload with the pan shaft 125 and mounting base. A housing cover713 includes a mating flange and static seal as described for cover 113,and payload 434 can have an air valve 150 to purge and pressurize theinterior with conditioned gas. With reference to FIG. 35, a top view ofdevice 401 illustrates the shifting of tilt shaft 105 off the panningaxis; the cover 413 and top payload 434 have been omitted for clarity.Tilt shaft 105 can also include a shaft coupler 188 as illustrated inthe tilt shaft configuration of FIG. 23.

Belts require that one or more pulleys or idlers be adjustable toinstall, tension, and uninstall the belt. Prior art has fixed the shaftgear and permitted the motor and motor gear to slide towards and awayfrom the shaft gear, with fasteners moving within slots in motoradjustment plates. With reference to FIG. 10, motor mount brackets 115and 282 can adjust the position of the motor gears 104 and 114 totension their belts, with the plates then locked into position by thefriction of the bolt heads on the sides of the slots. This bolt headfriction may not be sufficient to maintain motor bracket position underhigh shock and vibration. With reference to FIGS. 48-50 is a linear geartrack and pawl which can permit incremental motor mount advancement thatcan maintain belt tension if the bolts loosen and fail to hold the motormount 282 in place. With reference to FIG. 49, a top view illustrates apawl 680 which can be fastened into the floor of a housing with ashoulder screw 684. The tip of the pawl can fit into teeth grooves of alinear gear track 685 rigidly attached to an adjustable pan motor mount282. As the motor mount 282 advances forward towards front wall 122, panmotor gear 104 increases the center distance to pan shaft gear 127. Atorsion spring 682 constrained between a shelf in the pawl 680 and anobstructing pin 682 can apply a constant force driving the tip of pawl680 into the grooves of linear gear 685. With reference to FIG. 50, anunderside view of the pawl and gear assembly illustrates a lock pin 681that can help hold the pawl 680 in position once the proper belt tensionhas been reached.

With reference to FIGS. 51-60 are an alternative motor mount retentionapparatus using a screwed wedge technique that has been applied to CNCmachining work holding vises. With reference to FIG. 60, tilt motormount bracket 115 can have a sloped side that is pressed upon as a wedge670 is lowered by turning screw 671. With reference to FIG. 51-53 aretop, side, and front views of a compact work holding vise which pushesout jaws 673 as a screw 671 lowers wedge 670. To keep the separatepieces together, a spring or elastomer ring 674 can be in guides 675 topull the jaws and wedge back together when the work pieces need to beremoved from the vise; the positioning device does not need suchfeatures as tensioning is only applied once or twice at the factory, andon rare maintenance. With reference to FIGS. 54-57 are top, side, sidesectional, and front views of a modified vise for linearly displacingand locking an adjustable component in one direction, as opposed to thebidirectional action of the standard vise. With reference to FIG. 56, aright side of wedge 670 can be straight and not apply lateral force thatwould otherwise displace the right jaw 673. With reference to FIGS. 58and 59, pan bearing flange 129 can include straight-walled backstops toprevent wedge 670 from pressing into the immovable pan bearing flange129, while also supporting the wedges as the tensioning belts resistdisplacement of the motor mount plates 282 and 115. As the screws 671turn, the motor mount plates will slowly advance to tension the beltsand non-permanent threadlocker can set the screws 671 in position tomaintain belt tension throughout vibration and shock.

With reference to FIGS. 61-64, a pan shaft 125 can have features whichmate with a mounting fixture 605 that can be rapidly locked down andreleased by a hand-operated toggle-clamp. With reference to FIG. 61, panshaft 125 of positioning device 101 can stand on three legs: a rightrear leg 615, a left rear leg 625, and a front center leg 635. Withreference to FIG. 63, the legs can be placed atop a mounting plate 605which is attached to a base such as tripod 602. To mount the pan shaftfirmly in the mount, the pan shaft 125 can be pulled to the right, awayfrom mount plate side 606, with a rod 625 that can slide up a slope 608in mount plate 605 until it is obstructed by a wedge 604. With referenceto FIG. 61, a hooked toggle point 612 is rigidly attached atop front leg635. With reference to FIG. 62, a latch 613 of a toggle clamp 617 canengage the anchor 612 to pull pan shaft into the locking wedge 604 asthe handle of clamp 617 is pulled to the closed and locking position.The locking draw stroke can also mate the electrical connector 141 to anexternal cable. To rapidly release the positioning device, the handle ofclamp 617 can be pulled upward which can push the pan shaft 125 out ofthe wedge and disconnect the connector 141, then the latch 613 can belifted off the toggle point anchor 612, permitting the positioningdevice to be removed from the mount.

DETAILS OF THE INVENTIVE POSITIONING SYSTEM DESIGN

The inventive positioning device is a device which can be mounted toboth mobile and fixed platforms. A fixed platform is commonly a tallCCTV pole, a bracket permanently mounted into a building edifice, or afixture in a robotic assembly line. The device mounting to such fixedplatforms is typically a semi-permanent installation, with removal onlyto perform maintenance or replace the device. Similar to the tire on avehicle, these installations are typically for long periods, must besecure, and are difficult and tedious to perform. Removal is furtherhampered by placing the devices atop mounts, high out of reach ofvandals, along with using high-security bolts with thread-lockingcompound.

A mobile platform can be a manned or unmanned vehicle such as a policecar, aircraft, ATV, boat, or robotic sentry. A mobile platform can alsobe a person or animal. The positioning device was conceptualized tosolve the challenges indoor and outdoor robotic devices, with outdoorpositioners aiming payload devices—such as cameras and lasers—as a fieldof robotics as a market with increasing demand yet underperformingtechnology. Mobile deployed positioning devices and robots have a highincidence of failure to mechanical shock—such as being dropped on theground—as well as weather and electromagnetic hazards. Beingparticularly hardened against these threats due to the novel bearing andpower train employed, it is expected the positioning device will havethe most market penetration in this outdoor, mobile space.

A user need for compact, portable equipment such as the positioningdevice is the ability to quickly and easily install and remove theequipment from a mobile mounting platform. In the case of a BorderPatrol unit, an agent may be driving an off-road vehicle through thedesert with the positioning device attached to the roof or a mast,equipped with a night vision payload. When said agent reaches asurveillance hide to begin a mission, he may then desire to quicklyremove the positioning device from the vehicle and mount it to a tripodpositioned in the concealed hide position. The positioning device andmount must have interworking features to provide the payloads a stable,level, and backlash-free platform. Once a target is located with thepositioning device, the agent may need to rapidly remove the positioningdevice from the tripod, reinstall it upon the vehicle, and begin apursuit. Should the agent come under attack, such a rapid and easydismount and mount process may be a life-saving feature, and also anequipment-saving feature since the device need not be abandoned in ahasty retreat. When the Border Patrol agent returns to the outpost, thecompact, portable positioning device can be quickly and easily removedfrom the vehicle and secured in a storage locker out of reach ofthieves, vandals, and exposure to the environment's hazards.

Prior art has predominantly used bolts and/or tongue-in-grooveinterfaces to mount mobile equipment. One need only watch the film AChristmas Story, the scene in which the main character is aiding thechanging of a flat tire, to foresee the problems in using loosefasteners at night or challenging conditions. Lack of ample illuminationmay prevent the operator from locating the fasteners on the mount, andmay misplace fasteners or the tools in the process. In a covertsituation, flashlights may not be an option, leaving the operator torely on touch and spacial relations to perform the mount and dismountoperation. Fasteners have an additional drawback as frequent mount anddismount cycles may strip to tool, bolt heads, and threads. In stressedsituations such as battle, a medical procedure, or a tight productionschedule on a robotics assembly line, human operators may not have thefine motor skills to operate tools, nor the cognitive capacity toremember and perform a complex mounting/dismounting sequence. Coldweather may also eliminate fine motor skills, and the operator may bewearing gloves that prevent manipulating small tools and complex matinggeometry.

Some examples of prior art positioning devices and portable payloaddevices have eliminated most or all bolts from their mobile mountdesigns, but most of these solutions have supplanted the fine motorskill dependent bolting method with another fine motor skill dependentmating feature, and many still include small features such as ball locksecurity pins. Small security pins can be ball lock pins where aspring-loaded ball bearing is recessed into the shaft of a pin, whileanother type of security pin includes a spring-loaded plunger; in bothcases, the ball or plunger pin aligns and snaps into place when a matinghole in the mating structure aligns with the ball or pin. These featurescan be difficult to engage and lock when the alignment hole is not veryprecisely aligned with the pin. Debris, such as dirt and ice, may causethe spring action to get stuck. The pin locking action may also producean audible snap unsuitable for covert operations. The security featurecan also be a simple pin on a lanyard, as simple as a screw-driver on astring attached to the mount fixture, that inserts through holes in thepositioning device and mounting fixture that align. In one example ofprior art currently viewable at URL“http://www.youtube.com/watch?v=kWuvyTB6OxQ”, a mobile surveillancetrailer includes a quick-mount system comprising a compact positioningdevice with an attached mount plate, a mating shelf rigidly attached tothe mast of the surveillance trailer, a straight security pin on alanyard, and an electrical cable. The positioning device is designed tomount to fixed structures with bolts, but instead in bolts into anaccessory base plate. This plate and the shelf on the trailer have atongue-in-groove mating permitting the positioning device base plate toslide into guides on the shelf. To prevent the baseplate from slidingalong the grooves backwards, a simple security pin is dropped throughaligning holes on the base plate and shelf. A cable for power andcontrol is then connected to the positioning device. Operators may notbe satisfied with this design. A mounting plate has been affixed to thestandard positioning device, which has added weight. While it permitsmodularity to avoid using a mobile mount for fixed installations that donot need a quick-disconnect, it adds weight compared to a design thatintegrates the mounting geometry into the fixed shaft of the positioningdevice. The tongue-in-groove may not be ideal in the challengingsituations described above. The mating interface is a tight fit betweenthe tongue and groove, and the operator must carefully align the tongueinto the grooved fixture before sliding the plate forward. Debris andice on the grooved fixture may obstruct the mating plate, and thesetightly interfacing tracks may not be able to interoperate if, ascommonly occurs in the field of this device, the positioning device isdropped and the precision mating tongue is bent.

With reference to FIG. 63, illustrated is a rigid and backlash-freemounting apparatus 601 for equipment that must be quickly and easilyinstalled and removed. This design can permit a mating procedure thatrequires no tools, few steps, and little or no fine motor skills. Avariety of features on the fixed shaft 125 of the positioning device canattach and rigidly mate with a mounting fixture on or attached to thefixed or mobile platform 602. In the illustrated embodiment, theplatform can be a tripod. With reference to FIG. 61, the base of the panshaft 125 can include three legs 615, 625, and 635. Between two legs615, 625 can be a rod or wedge 603, the mating rod (‘rod’). This rod canbe a separate piece that is threaded and rigidly attaches between thetwo legs 615, 625, or the rod 603 can be an integral feature between,and integral to, the legs 615, 625. With reference to FIG. 63, the rod603 mates with a mating notch 604 (‘notch’) in a mating mounting plate605 (‘mounting plate’) which can be attached to or integral with themounting base platform 602. The positioning device 101 can be gripped bythe installer, and the back legs 615, 625 with the rod 603 can makecontact with an end 606 of the mounting plate. The mounting plate 605can have upright guide posts 607 at this end 606 that are angled andbeveled to catch, guide, funnel, or otherwise align the legs 615, 625and rod 603 into a desired position. Such funneling features canaccommodate and correct sloppy placement by the operator, such as fromusing only gross-motor skills in a stressed environment, using gloves,or having poor visibility. Once aligned, the positioning device 101 canbe pulled toward the operator, away from side 606, with the funnelfeatures 607 continuing to guide and align the three legs without thefine interplay required by a tongue-in-groove. The rod 603 can thencontact an upward slope 608 in the mounting plate 605 that elevates thepan shaft 125 off of its rear legs 615, 625. This slope 608 can have acurve or reverse in direction to form a “V” or “U” wedge 604 (‘wedge’)that blocks farther travel by the rod and attached positioning device101. The top side 609 of this wedge 604 overhangs the mating area withthe rod 603, an obstruction which can serve as a roof to shield thewedge from debris and weather. The rod and wedge surfaces can beprecisely manufactured to be straight and flat surfaces to maintainprecise and accurate alignment of the pan shaft 125 with the mountingplate 605, such that the positioning device can have a level platform.The mounting plate or pan shaft can include a bubble level 611 or levelsto permit a level base for the positioning device 101, and thepositioning device can include sensors such as a digital embeddedcompass to detect the mounting error. A third, frontal leg 635 on panshaft 125 can be the same length as rear legs 615, 625 to mount levelatop the mounting plate 605, or this front leg 635 can be longer thanthe other legs in an amount equal to the difference in vertical heightthat the bottom slope 608 of the wedge elevates the rod 603. The base ofpan shaft 125 can also be slanted toward or away from the direction ofthe user's pulling action to optimize leg height, rod position, andwedge size. With the rod 603 tightly in the wedge 604, the positioningdevice 101 is constrained in two axes, but not in the axis in which itus pushed or pulled, nor is it rigidly held into place.

To draw together and lock the positioning device into place, a handoperated toggle clamp can be used. Toggle clamps can have hundreds ofpounds of clamping force that securely hold the positioning device inplace throughout drops or a rough ride on an off-road vehicle, yet is asimple, tool-less design that has few operating steps and requireslittle or no fine motor skill to mount or dismount, with more detailsdescribed in “EP 1169235 B1, Toggle-clamp for fastener”. Toggle clampssuited for vibration, inverted position, slightly short of centerclamping, and other variable conditions is described in “U.S. Pat. No.5,165,148, Toggle Clamp with Locking Mechanism” and “EP 1967324 B1,Universal locking mechanism for a clamp”. With reference to FIG. 64, atoggle clamp can be rigidly attached to a mounting surface, and caninclude a hook, latch, lasso, or magnet 613 (‘latch’) that can beextended toward an anchor point on the equipment. By pulling the clampinto a locking position, the equipment is pulled at it's anchor by thelatch. Once fully drawn, the clamp can include a safety mechanism toprevent unintentional release of the clamp.

With reference to FIGS. 61 and 62, in the illustrated embodiment, atoggle clamp apparatus includes an anchor 612 that can be rigidlyattached to pan shaft 125, with tapped threads, threaded inserts, orother fastening points on the shaft 125 as the standard mountingprocedure. A toggle clamp 617 can be rigidly attached to the mountingplate 605. The clamp can be pushed open by the user to extend a hooktype latch 613 which can engage with the anchor 612; the full draw ofthe toggle clamp 617 can be sufficient to pull the rod 603 up the slope608 of the wedge 604 and can hold the rod securely in the wedge withouta loose fit or play between the rod and wedge. With reference to FIG.64, the toggle clamp 617 can include a thumb paddle 618 permittingone-handed positioning of the hook 613 so that an operator's second handcan draw and hold the rod 603 into place in the wedge 604. The toggleclamp 617 can also have a safety lever 619 that may prevent shock,vibration, or operator error from knocking the clamp 617 into the openposition unintentionally. The funneling guide posts 607 in the mountingplate 605 as well as the wedge structure 604 can be thick and strongfeatures that resist denting as opposed to a tongue-in-groove guide, andthe rod's mating face can be somewhat shielded underneath the pan shaft125, held between the two rear legs 615 and 625. There is little or noexposed, complex mounting geometry to be damaged from drops, and debrisis less likely to work into the mating features.

With reference to FIG. 63, as an additional improvement, the operatorcan have an installation and removal procedural step eliminated byintegrating a push-pull type electrical connector plug 142 into themounting plate 605 can engage with a mating push-pull connectorreceptacle 141 in the pan shaft 125. The pan shaft legs 615, 625, 635,pan shaft slope 608, and mounting surface flanges 622 of the matingconnectors 141, 142 can be sized and angled to cause the connectors tomate by the user's drawing action of the toggle clamp 617. The hook 613length, draw stroke, separation between anchor 612 and the clamp, andwedge 604 geometry can be precisely tuned such that the full stroke ofthe clamp 617 performs a full mating of the connectors 141, 142, and afull mating of the rod 603 into the wedge 604. The rod, wedge, or bothcan be coated with a deformable coating, such as an elastomer, thatprovides grip between the rod and wedge while relaxing some of theconstraint such that the connectors 141, 142 can have some play andtolerance in aligning their pins and sockets.

Mobile equipment such as the positioning device 101 can be heavy andtedious for operators to transport and handle. Fatigue and lack ofgripping surfaces can lead to the equipment being dropped to the groundand damaged. Prior art has included drawer-type handles fastened topayloads or the positioning device for users to carry, but rigid handlesare obtrusive and add weight. Prior art has also attached an eye-bolt tothe positioning device for operators to stick a finger through andcarry, but some fingers or gloved hands may be too large for the eye ofthe bolt, the steel bolt adds weight, and the tapped hole may be largefor a large bolt. A carry system familiar to users of high performancesurveillance equipment are rifle slings. One such sling system usesquick-connect/quick-disconnect ‘QC/QD’ hardware to attach and remove thesling in seconds, described by application “US 20120174458 A1,Detachable Swivel and Associated Mount”. Similar rifle slings may betailored for carrying objects other than firearms, such as thatdescribed in “U.S. Pat. No. 6,932,254 B2, Sling for carrying objects”.Another carrying accessory offered by the referenced sling manufactureris a Universal Wire Loop lanyard, viewable at URL“http://www.blueforcegear.com/universal-wire-loop/”. These are all lightweight, flexible, and removable carry systems that can make thepositioning device more easy to transport and less prone to drop-induceddamage.

With reference to FIG. 63 the positioning device 101 can includethreaded holes or posts 614 to attach a carry handle, lanyard, or sling.In an embodiment, two posts 614 on pan shaft 125 can accept standardQC/QD hardware for rifle slings. In another embodiment, a smooth hole orpost on pan shaft 125 can accept a loop of cordage or wire such as thaton a Universal Wire Loop, and this post 614 can bear the weight ofpositioning device 101.

With reference to FIG. 4, a block diagram of the positioning device 101is illustrated. In order to use the positioning device 101 to positionthe devices 134,136, a power supply 571 can provide electrical power tothe electrical components including the pan motor 102 and the tilt motor112 within the housing 111. The power supply 571 may also provide powerto the external controller 573 in many embodiments. The power supply 571can be a battery, a generator, a connection to a power grid or any othersuitable electrical power supply. Thus, the power supply 571 can have anAC or DC input and may provide output electricity as an AC or a DCvoltage. In an embodiment, the positioning device 101 can have aninternal isolated AC/DC or DC/DC converter 118 to provide conditionedpower to the pan motor 102, the tilt motor 112, or any other electricaldevices mounted on or within the positioning device 101. The choice ofthe power supply 571 voltage configurations and the converter 118voltage configurations can be based upon various factors including: thecompatibility of the motors, transmission losses in cable runs, and thepower source (grid vs. battery). The external supply 571 is commonly aCCTV power supply operating off an electrical input of 110-220 VAC inthe USA and producing an electrical output of 24-28 VAC, 12-28 VDC, orup to 57 VDC when the power supply 571 is a power-over-ethernetinjector. The output of the power supply 571 can be selected as DCoutput for short cable runs, and AC for long cable runs to minimizetransmission losses. The internal converter 118 can be selected tosupply conditioned AC or DC output to support the motors' native AC orDC operation, and the internal converter's 118 input can be selected asAC or DC based upon the output from the power supply 571.

The positioning device 101 may also be in communication with acontroller 573 and a user interface 575 to control the position of thedevices 134, 136. An operator may input control commands into the userinterface 575. The command signals can be transmitted to the controller573 which converts the command signals into individual control signalsfor the pan motor and the tilt motor. The user may also input devicecontrol signals into the user interface 575 which are transmitted to thecontroller 573 which then transmits the control signals to the devices134, 136. Some devices 134, 136 such as cameras, distance measuringdevices, audio monitoring devices and other mechanisms can provideoutput signals. The output signals from the devices 134, 136 can betransmitted to the controller 573 and to the user interface 575. In anembodiment, the user interface 575 can be remote from the controller573. In these embodiments, the controller 573 and user interface 575 mayeach have transceivers for wired or wireless communications. Thecontroller 573 can be an example of an external processing module,typically performing video processing and encoding, video recording tohard drives, auto tracking of moving objects, gyro-stabilization,control protocol translation, and media conversion which can beRS232/422 to fiberoptic or RF wireless. An additional internalcontroller 574 can be housed inside the housing 111 to drive the motors,sense shaft position, switch video channels, monitor environmentalsensors such as temperature, translate protocols from various thirdparty CCTV controls, and an advanced implementation of controller 574can assume all tasks of external controller 573.

With reference to FIG. 36, the core technology of the inventivepositioning device is the bearing system design, enabling a smaller,lighter, simpler, less expensive, more reliable product to be builtaround this bearing platform. The described embodiments of thepositioning device can include bearings for panning payloads and caninclude bearings for tilting payloads. The turntable bearing 391 hasrobust load handling capacity and may perform acceptably as the solebearing supporting a rotary shaft. For devices deployed far frommaintenance depots, or for deployments where reliability is paramount,such as battle and rescue, a second supporting bearing or bushing can beadded to the shaft. With reference to FIG. 17, payload 136 is a distancefrom tilt shaft gear 131 that could induce high moment loads. Lack ofconcentricity in the tilt shaft 105 or misalignment could lead togrinding of the shaft 105 where it enters the bore in wall 123, andshaft deflection could deform dynamic shaft seal 152 on side 123 to thepoint leakage occurs. A small, low-profile bearing or bushing 144 can beadded in wall side 123 to constrain shaft deflection. Tilt shaft 105bearing 144 can be a thin-section radial bearing with an outer racetightly press-fit into a bore on housing side 123. A tight press-fit isan interference fit where the softer mounting surface material warps andenvelops the steel of the radial bearing race for a permanentinstallation. The bearing seating bore can be fabricated with aprecision surface finished and dimensionally toleranced to a thousandthof an inch error or less to reduce the possibility of an undersized borewarping the bearing steel under the tons of force applied during thepress installation and remaining thereafter as static load. In somecases, a manufacturing or assembly defect may occur where the bearing144 may not be seated flush into the bore by the press-fit installation,preventing the shaft from rotating with even, concentric motion. Thisuneven seating creates a misalignment error that can also impart unevenloads down the shaft sufficient to damage paired bearings or other shaftcomponents. Press-fit bearings may be improperly seated or damagedduring or after installation to a degree that the system cannot functionas intended. Because the precision mounting surfaces are deformed tocreate the interference fit, there are no second chances to reseat thebearing. The surfaces cannot have a new bearing press-fit over them; anychassis or shaft with a tight press-fit with the damaged bearing must bedisposed of along with the bearing. The installation process can alsoinclude heating or application of tons of force that—appliedimproperly—can damage the bearing. Even if the product leaves thefactory with perfectly press-fit bearings, the deployed device mayencounter shock, vibration, or contaminants that permanently damage ordestroy the bearings. To reduce transmittance of damaging shaft loadsinto the radial bearing 144, the inner race can have a loose press-fitwith the tilt shaft 105 such that the shaft can be removed and does notimpart damaging axial loads into the radial bearing. A loose press-fithas little or no deformation on the mounting bore or shaft, but is notas rigid a bond. Because the light press-fit does not transfer axialloads into the bearing, this bearing 144 can use rolling elements andraces optimized for radial and moment loads, such as a radial ballbearing. With reference to FIG. 30, bearing 144 can be a bearing with anouter race which has been installed into shaft mount bracket 145 and canhave a tight press-fit. Bracket 145 can be fabricated with a precisiontoleranced and surface finished bore for a proper fit with bearing 144.If the bearing 144 is improperly press-fit, the bearing 144 and bracket145 can be discarded before installation into housing 111. If thebearing has been damaged in service, the light press-fit enables thetilt shaft 105 to slide past the inner race and bracket 145 can beremoved from wall side 123 by removing the fasteners and alignment pins138 (not visible) anchoring it into the wall side 323. With reference toFIG. 21, the outer race of radial bearing 143 includes an integralflange that can have mounting holes to rigidly attach bearing 143 insidea bore on housing side 123. This integrated bearing may be simpler andless costly than mounting a unflanged bearing 144 into a separatebracket 145. The flange and mounting holes with fasteners add complexityto the wall side 323 and may not have as high load capacities andalignment as a press-fit bearing, but the ability to remove bearing 143could prevent the highly integrated monocoque housing 111 from beingdisposed of along with a permanently press-fit bearing 144 that has beendamaged.

In a precision positioning device, even minor damage to rolling elementsand races can lead to unacceptable friction and torque inconsistencies.A widely deployed example of prior art employs pairs of sealed radialbearings such as bearing 144, or possibly deep-groove radial Conradbearings, and damage to these positioning products has been reported bysome customers as occurring often under the environmental threats andrough handling associated with outdoor, mobile robotics. Anotherpurchaser of military surveillance gimbals also has recently expresseddisdain with which existing pan-tilt positioning devices are failingquickly and repeatedly from damage to bearings after rough transport andhandling by military personnel and vehicles. Due to the permanence ofthe press-fits, large assemblies of housing panels and shafts attachedto the damaged bearings must be replaced along with the bearings,resulting in expensive, laborious repairs for the manufacturer ordefense depot and long service outages to users.

Load vectors exerted onto bearings can be classified as radial, axial,moment, a combination of the three, and can be applied uni-directionalor bi-directional. A variety of bearing designs exist to tailor loadcapacity for a particular application. A significant discriminator inthe selection process is the rolling element shape; contact bearingstypically contain either spherical or cylindrical rolling elements. Ingeneral, a sphere can be made more accurate and for less cost than acylinder. While tapered and crossed roller bearings can be found inheavy machinery, where their very high load capacities are required,ball bearings are better suited for smooth, precision robotics such asthe positioning device 101. Radial ball bearings like balls 135 inbearing 144 are optimized to handle high radial loads, but are not thebest option for handling the other load types. The deep-groove Conradradial bearing includes axial load handling features but cannot handlemoment or combined loads well unless paired with a second Conrad bearingfurther down the shaft. The ball separator cage of the deep-grooveConrad arrangement also prevents a high ball complement, resulting inlow load capacity compared to other arrangements of the same bearingsize. Angular contact bearings handle moment and axial loads better thanthe deep-groove radial type but are not equipped to handle radial loador bidirectional thrusts, therefore the common pairing of a singleangular bearing with a radial bearing will still leave the equipmentvulnerable to bidirectional axial loads. Because robotics such as thepositioning device 101 can be subject to extreme shock and vibration inany direction, there can be no gaps in coverage of load vectors. Abetter all-around option is the four point contact bearing as it handleseach load direction, combined loads, and bidirectional loading well.With reference to FIG. 42 providing a detailed view of the rollingelements and races, a view of bearing 391 shows ball bearings 135 rollwithin grooves 393 formed in the inner ring 133 and the outer ring 137.The grooves 393 can have a shape that is recessed from the bearings 135so that only the edges of the groove 399 are in physical contact withthe bearing 135. The illustrated groove type is the Gothic Arch raceway.The bearing elements can be a single row of four point contacted ballswhich can have a 30 degree contact angle. In an embodiment, the groovesof bearing 391 can be gothic arched races with 4 points of contact uponthe balls. This configuration is known as 4-point bearing and providesbearing support for radial, axial, moment and combined loads. The4-point Gothic Arch configuration may have lower stiffness and staticload capacity than a roller bearing, but it typically has higher dynamicload ratings which are likely to occur in a device which may be rotatingthe shafts when an impact is received. Because a light press-fit isdesirable between the tilt shaft 105 and supporting bearing 144, littleto no axial loads will be seen by bearing 144, thus choosing bearing 144as a radial bearing will optimize it for the loads it is likely to see.Bearing 144 can be a thin-section bearing to minimize size and weight.

Precision positioning applications require a very stiff bearing tomaintain high repeatability of position indexing, and the slow, finemovements of precision positioning benefit from drives with low torquedrag. In applications which require greater stiffness and lower torquethat a four-point contact ball arrangement, yet still with a single rowof rolling elements for a compact size, the single rowed crossed-rollerbearing is the best alternative. With reference to FIG. 45, a embodimentof an externally geared turntable bearing 391 includes an outer ring 137and inner ring 133 which glide past each other via a single row ofcylindrical roller bearings 335. Oriented in alternating axes ofrotation within “V” shaped grooves 393, this positioning of the rollerelements enables turntable bearing 391 to accept all combinations ofthrust, radial, and moment loads. A cylindrical roller of approximatelythe same size as a ball has a greater load carrying ability than theball alone, but the crossed roller orientation has a reduced moment andthrust capacity compared to the 4-point contact design with ballbearings due to each roller carrying loads in only one direction whileall balls in a 4-point groove work together to handle all directions atonce. This moment and thrust disadvantage is offset by gains instiffness and rigidity afforded by the larger contacting surface areaand geometry of the roller element, and gains in rotational torque dragperformance are achieved because each roller is oriented to transferload in only a single direction instead of every direction. Asimplemented in the inventive device, turntable bearings of approximately12″ or less have fewer bearing elements and thus are not appreciablyaffected by the rotational torque losses of a 4-point design over acrossed roller. The small size of the turntable bearing also prevents areduced stiffness rating of the four point configuration from adding upto unacceptably sloppy precision and repeatability demanded of large,long-range positioning devices. With reference to FIG. 46, a turntablebearing 391 has a roller configuration orienting a row of cylindricalrollers 335 in each of the three load directions. This triple-rollerbearing has full coverage of all loads, but is too bulky, heavy, andexpensive but may be necessary for proper load handling and stiffness ofscaled up embodiments of the positioning device 101. A bearingmanufacturer recently announced a dual-row roller bearing, with smallcylindrical rollers, with the smallest diameter offered around 12″; sucha bearing can have high stiffness, low torque, and very high loadcapacity as required by large positioning devices aiming long-rangepayloads.

A third suitable alternative to the 4-point contact turntable bearing391 is an integrated super-duplex angular contact bearing and raceassembly. Where the external race is not split, an external gear profilecan be hobbed into the race or a separate pulley ring can be rigidlyattached around the race. The outer race can also be widened to createan outer ring, with mounting and alignment holes. With reference to FIG.43, turntable bearing 391 has an outer ring 137 with mounting holes andcan have external gear profile on the outer circumference. An inner ring237 is split to permit assembly, the rings held together and pre-loadedby a presser flange or fasteners. As with all bearings considered foruse in the positioning device 101, the balls and races can be protectedfrom contaminates by face seals 160, and additional protection can beoffered with rigid shields 161 to enhance free-state bearing stiffness.The additional row of balls adds torque drag and weight, so balls 235can be constructed of a lighter material such as silicon nitride.Silicon nitride balls are lighter than steel balls and can be lightlyoiled instead of greased, increasing survivability under marginallubrication. Silicon nitride balls are very stiff and do not conform toraces like steel balls, having a smaller contact ellipse. This reducedcontact reduces friction and starting torque which can enable smaller,finer movements of the shaft. This reduced contact has a drawback inthat impact load capacity may be reduced approximately 30% in asingle-row four-point arrangement. While a poor selection forsingle-rowed embodiments of bearing 391 in high-shock environments,duplexed rows can overcome this weakness. Duplex bearing 391 caneliminate the ball separator 162 and particle shedding associated withseparator rings by alternating silicon nitride balls 235 with slightlysmaller steel spacer balls 135, though no preloading could be applied tothe steel balls. With reference to FIG. 44, split inner ring 233includes integral fasteners to fill the balls and assemble the ring witha pre-load to the balls 135. Ring 233 can include another hole patternfor mounting the bearing to a surface with fasteners. Outer ring 137 canbe a one piece ring and can include an external gear profile. Balls 135can be steel balls separated by separator rings 162 made of Delrin,brass, or similar low friction material. The two rows of balls can havetwo points of contact between each ball and the races at points 399. Thecontact points of duplex bearing 391 in FIG. 44 illustrate aface-to-face super-duplex angular contact bearing while the contactpoints of duplex bearing 391 in FIG. 43 illustrate a back-to-backsuper-duplex angular contact bearing.

An existing technique used to improve the reliability of rotary shaftswith paired bearings is to team dissimilar bearings and vary the levelof press-fit. In dissimilar paired bearings upon a rotary shaft, thepress-fit on each race can be adjusted tight or loose in order tochannel loads to the bearing equipped to handle them best; for example,a sub-optimal decision in shaft design is to tightly press-fit bothbearings, often both radial bearings, upon the shaft. Thermal expansionand contraction of the shaft length can create an unintended axialpre-load in moderate temperature fluctuations, with extreme temperaturesexpanding or contracting enough to permanently deform the balls orraces. Reducing the risk of this axial loading can require finermachining tolerances and derating of the operating loads of the product.Alternatively, one of the bearings can have a light press-fit upon theshaft so axial loads such as impacts or thermal expansion result in theshaft slipping past the bearing race it is lightly attached to. In FIG.17, radial bearing 144 can have a loose press-fit on the tilt shaft 105so all or nearly all axial load channeled down the tilt shaft 105 can behandled by the 4 point contact structure of tilt bearing 131. Whileangular and radial bearings can be paired on a shaft to utilize theirrespective strengths to handle combined loads, such as with a tightlypress-fit angular bearing tasked with axial and moment loads while alightly press-fit radial bearing handles radial loads, this delegationof loads between them may not be as simple or inexpensive as employing asingle bearing designed to reliably survive all loads a device mayconceivably experience. Tightly press-fit bearings can also comedislodged, especially from improper mounting, and this disabled bearingmay expose the second bearing to loads it is wholly unsuited to handlealone.

Tilt shaft bearing 131 can reliably handle significant loads seen ontilt shaft 105. Because the four-point contact bearing can handle allforeseeable loads alone, the radial bearing 144 may not be required.Where an additional design safety factor is desired, bearing 144 can bea light, compact thin-section radial bearing, and can have a lightpress-fit upon shaft 105 to channel most loads to the capable turntablebearing 131. This radial bearing can handle radial loads by constrainingnon-concentric shaft wobble and limit the moment arm length of shaft 105from overloading the moment load capacity of the four-point contactturntable bearing. In embodiments where a shaft penetrates a second sideof the housing such as tilt shaft 105 penetrating housing side 123 orpan-thru shaft 425 of FIG. 34 penetrating through cover 413, a bearingor bushing can be installed around the shaft to permit smooth,constrained motion of the shaft through that second wall.

Turntable bearing 391 facilitates different mounting configurations tosupport a variety of shaft geometries to meet various design goals. Withreference to FIG. 36, a detailed above view of a turntable bearing 391is illustrated. With reference to FIGS. 37-41, cross section side viewsof a turntable bearing 391 are illustrated, with FIGS. 42-46 detailingviews of portions of embodiments of the turntable bearing raceways. Likemost contact bearings, the turntable bearings of FIG. 36-41 includebearing races 137 and 133 that rotate about each other via rollingelements such as ball bearings 135. Unlike most bearings, races 137 and133 have been expanded to unusually wide proportions in order to includeplanar mounting lands 166 and 168 and holes 395 for fastening the racesonto planar shaft and housing surfaces.

In order to facilitate different mounting configurations, the heights ofthe planar surfaces 166 and 168 of the inner ring 133 and the outer ring137 can be offset; for example, if the turntable bearing 391 is rigidlymounted to a planar surface of an object such as the positioning devicehousing 111, a portion of either the inner ring 133 or the outer ring137 can be rigidly attached to the planar surface. The portion of theturntable bearing 391 that is not attached can move relative to thefixed ring and should be able to rotate freely. The surface of therotating ring can be recessed relative to the adjacent fixed ring forfree rotation, as ring planar surfaces of the same height would lead tocontact and grinding of the ring which is not bolted to the flatmounting surface. There can be a small height difference between therotating ring and the fixed ring for clearance from a flat, planarmounting surface. As illustrated in FIG. 41, in an embodiment, the innerring 133 has planar surfaces 166 that are slightly higher than theadjacent surfaces 168 of the outer ring 137, creating a verticalclearance between the rings. The surface 168 of the outer ring 137 canbe rigidly attached to a planar structure below, and the inner ring 133will still be able to rotate freely, or vice-versa. These features alsoallow either the inner ring 133 or the outer ring 137 to rotate freelywhen the turntable bearing 391 is mounted to a large planar structure.With reference to FIG. 5, the pan turntable bearing 127 illustrated inFIG. 41 contacts the flat underside of pan bearing flange 129 withraised inner ring 133 while the slightly lower ring 137 can rotatewithout rubbing upper planar surface 168 on the underside of pan bearingflange 129. In other embodiments, the surfaces 166 of the inner ring 133can be lower than the planar surfaces 168 of the outer ring 137. Withreference to FIG. 40, the inner and outer rings can be the minimumthickness of strong material to handle the loads of the fasteners androlling elements, and the mounting surface can have a raised annularboss to offset one ring to rotate free of the mounting surface. Withreference to FIG. 6, inner ring 133 is minimized in thickness whileouter ring 137 maintains a thickness suited for the belt. An annularboss on the underside of pan bearing flange 129 projects downward,inside the bearing, to reach upper planar surface 166. Instead ofbuilding up the bearing ring thickness to create an offset as in FIG.41, where such material may be heavy steel, a mounting surface oflighter material such as aluminum can supplant the steel by projectinginward to meet the bearing planar surface, reducing the total weight ofthe positioning device 101.

In FIGS. 6-12 and 14-16, the pan bearing 127 can be a turntable bearingthat is configured with the inner ring 133 rigidly coupled to thehousing and the outer ring 137 rigidly coupled to the pan shaft.Similarly, in the tilting device embodiments of FIGS. 17-22, the tiltshaft gear 131 can be a turntable bearing with the outer ring 137rigidly coupled to the tilt shaft 105 and the inner ring 133 rigidlycoupled to the wall of the housing. FIG. 17 illustrates the flexibilityin shaft diameter sizing afforded by mounting each ring to a flange;tilt shaft flange 107 can by very narrow to minimize the bore in wallside 121, or can be very wide like pan shaft 125. FIG. 13 is anexception illustrating that either ring can be coupled to the pan shaft;however, while such an embodiment would still greatly improve on priorart by permitting greater load handling and a simplified installationfree of press-fits, it would not have the additional benefits ofintegration and compaction afforded by the outer ring servingdual-purposed spinning freely as a shaft gear. Where shaft flange 229has a geared pulley overhanging the outer ring to vertically compact theshaft, there may be more misalignment and reduced concentricity of thebelt and pulley motion compared to the geared bearing.

Mounting-holed bearings usually mount to flat, planar surfaces and areknown as flat-mount bearings. With reference to FIG. 45, a popularimplementation of a flat mount bearing, the crossed roller bearing usesorthogonal rows of cylindrical rollers instead of balls to achieve veryhigh load capacity for applications such as heavy industrial machinery;however, these rollers are heavy, take up much more space than ballbearings, the cylindrical rollers are generally less precise thanspherical balls, are more expensive, and the assembled bearing has smallcentral bores 167 for a given outer diameter. The center of turntablebearing 391 can be a cylindrical opening 167 that allows othercomponents be positioned through the opening 167, such as wiringharnesses and slip rings, but this opening would be significantlyconstricted if the bulky cylindrical roller elements and races were toreplace the compact ball elements in small embodiments of thepositioning device 101.

Another detractor from adopting a roller bearing is the two-piece outerring of many flat mount and crossed roller bearings leaves a seam aroundthe circumference which may negate the possibility of gearing the outerdiameter. Teeth of both halves would have a gap in the middle, and teethhalves may not align sufficiently. Possibly one half of the split ringcould overhanging the other half. A separate pulley press-fit over bothrings is not usually possible as the press-fit pre-loads the split ring.With reference to FIG. 46, outer ring 237 is split and may not permitintegral gearing. With reference to FIG. 37, ball bearing arrangementssuch as the four point contact bearing are less expensive whileperforming smoother motion in a smaller and lighter package than taperedor crossed roller bearings employed in prior art, the mounting holes 395avoid the hazards associated with press-fits, and balls can be loadedwithout split rings.

The turntable bearing 391 can include mounting holes 395 and, in anembodiment, the inner diameter of some or all of the mounting holes 395can be threaded. Screws, bolts or other suitable fasteners can be placedthrough the mounting holes 395 to secure the turntable bearings 391 toother positioning device components. The inner ring 133 and outer ring137 of the turntable bearings can have mounting holes 395 which canallow the turntable bearing 391 to be rigidly coupled to other objectswith screws bolts or other fasteners. The mounting holes 395 can alsonegate having to provide presser flanges and bores for mounting thebearing 391, which can be necessary with many crossed roller andflat-mount bearings.

Press-fit bearings are mounted into precision bores and shafts thatalign the bearing and shaft components. Precision shoulders on thesebearings are expensive and it is also costly to produce tight tolerancesand high quality surface finishes on the bores they are mounted within.This is an expensive mounting compared to bolting down a flangedbearing, but is an effective way of aligning all shaft components.

Simply bolting a bearing down will not remove susceptibility to angularmisalignment where the mounting surface is insufficiently flat, axialmisalignment where the mounting surface depth and bearing cross-sectionare not axially controlled, or parallel misalignment where the mountinghole patterns are shifted off axis. To mitigate these sources ofmisalignment, the bearing and mounting surface can increase theirflatness and dimensional tolerances, while precision located holes foralignment pins 138 can reduce parallel misalignment. These refinementsadd cost. With reference to FIG. 39, planar mounting surfaces 166 and168 must be very flat to limit angular misalignment and alignment pinholes 396 enable precision locating the bearing to limit parallelmisalignment. As the shaft is elongated and bearing mount points grow inseparation, tolerances must reduce to keep misalignment within designparameters. With reference to FIG. 30, tilt shaft mounts 128 and 145 canhave alignment pins 138 or other mating features in wall sides 321 and323. To align shaft pieces of tilt shaft 105, the clamp in the centercan include a set screw, inline pins 138, or a keyway to both mate androtationally align the shaft ends. With reference to FIG. 33, the endsof tilt shaft 105 mate in a clamp which tightens with a fastener.

The two-piece shafts of the inventive device can include inlinealignment pins 138 to locate the turntable bearings 131 and 127 to thehousing, shaft flanges, and bearing flanges. Inline pins or keyways canbe used to keep the shaft pieces rotationally aligned, and keyways inthe shaft ends can also provide this alignment, but neither may preventaxial movement under heavy axial shock loads. Additional mating featurescan include a clamp structure where one shaft end envelopes andconstricts over the mating end of the other shaft, tightened by a bolt.A set screw can also be used to penetrate through the larger shaft endand press into the smaller shaft end, but this is a weak connection andeven a self-locking set screw can come loose under severe vibration andshock loads. For applications that require additional protection fromshaft misalignment, a shaft coupler can be used, discussed in detaillater.

An additional feature of the shafts is attachment of a rotary positionsensing apparatus. This position sensor can be used to coordinate thedriving of the motors to effect a desired rotational orientation of thepayloads, while simple binary flags can trip limit switches to preventover-rotation. In a device that has hard stops mechanically preventingrotation beyond a certain angles, such a limit switch can activate themotors or a brake to prevent slamming the shaft stop against the chassisstop. For shafts without a slip ring, with cables attached to orentering the shaft, over-rotation can cause excessive flex in the wiresor even yank them free of their sockets. This rotary position sensingapparatus can include a disc or projecting feature rigidly attached tothe shaft, with a read head to sense the position of the disc or featureas it rotates with the shaft. This feature can be an armature thatinterrupts an optical beam in the read head as it passes a pre-setposition, or a magnet can be embedded in the armature to activate a Reedsensor or other magnetic sensor. Where cables are near the armature,there is a risk of the arm catching the cables and cutting them orcatching them and pulling them out of their sockets. In this case, acontiguous disk can be used instead of the projecting arm. The disk canhave holes at predefined references aligned with the read head tointerrupt or pass the beam of an optical read head. The disc can alsoinclude one or more rigidly attached magnets to trigger a magnetic readhead. More sophisticated position sensors include incremental andabsolute encoders. Incremental encoders are typically a patterned discwith regularly spaced lines or features to pass or block a light beam,or similarly effect a magnetic field. Absolute encoders have more detailin the encoded pattern and electronics can process the read head to knowthe position without the startup calibration routine required for binaryflags and incremental encoders.

With Reference to FIG. 17, early described are simple mechanical hardstops integrated into the tilt shaft and tilt shaft mounting flange 241,whereby flange surface 628 obstructs tilt shaft key 191. FIG. 22includes a variation where tilt shaft flange pin 108 is obstructed byshaft mounting bracket 128, with another embodiment in FIG. 23 where pin108 is on the opposite side of the tilt shaft flange 107 and strikes afeature 109 on the underside of cover 113. Because these stops can bedamaged by rapid rotation of the shafts into them, warning sensors canbe integrated with the shafts to monitor the shaft rotary position. Aread head 146 is precisely located upon housing 111 to read features ontilt shaft flange 147. Flange 147 can be rigidly attached or removable,and can have a keyway or other alignment feature to reduce any alignmenterrors between the disc and the true shaft position. Where shaft mounts128 and 145 are removable brackets, dowel pins 138 can aid inmaintaining a true rotational reading between the shaft and read head.Similarly dowel pins or keyways in the coupling joint of tilt shaft 105can keep a tight rotational relationship between the flange 147 andmechanical stops of tilt shaft pin 108 and roof stop 109. Alignment pins138 in holes 396 of turntable bearing 131 also aid in angular alignmentof the disc 147 such that it remains parallel to the reading slot ofsensor 146. By using a sensor and tightly aligned shaft, controller 573or integral motor control electronics in the motors can sense the shaftrotary angle and initiate braking to avoid a crash into the mechanicalstops.

A benefit of turntable bearings like 391 is that they serve as combinedbearings and gears in the same envelope. Bearings typically mountbetween a shaft and housing via their inner bore and outercircumference, but the addition of mounting holes leaves these surfacesfree. Prior art press-fits or fastens gears or pulleys onto shafts inaddition to pairs of bearings, resulting in tall shafts with severalprecision stepped diameters. With the outer circumference free of therole of press-fitting into the chassis or shaft, a geared ring can bepress-fit around the bearing exterior to create a gear or pulley out ofthe bearing. The geared ring could damage the coupled drive gears orbelts if not installed very parallel. To avoid this source of error andadded cost of the separate ring, hobbing gear teeth directly into theouter circumference of the flat-mount turntable bearing yields a thesingle package performing the combined roles of a bearing andgear/pulley. Such integration reduces system complexity, size, weight,and cost while improving reliability and serviceability. Integrallygeared mounting holed bearings have been around in the form of slew ringbearings, but not in the form of bearing 391.

Slew ring bearings have been nearly exclusively used for geared drivesby spur or worm gears as the typical applications have been massive,heavy, fixed in location, and thus not likely to develop backlash. A newclass of slew rings is much smaller, used in applications includingsolar trackers and scientific turntables, hence “turntable bearing”, yetthese bearings continue to be predominantly gear-driven, heavy, andstatically deployed in low-duty operation. In contrast, the presentpositioning system is directed towards a much smaller device that aimsto be smaller yet through component integration. The turntable bearingsin the inventive positioning device can be about 2.5 inches in diameterto about 12 inches in diameter; however, in some embodiments withheavier loads, larger slew or turntable bearings such as 24 inches indiameter or larger can be used. For small applications that are mobileand need near zero backlash and no exposure to teeth snapping orseizing, a synchronous belt driven turntable bearing offers a rugged,compact drive with greater dynamic combined load capacity than priorart's use of paired bearings, and the belted outer ring eliminates theneed for a separate shaft gear and shaft complexity to mount the gear orcut it directly into the shaft. The compact turntable bearing withintegrated pulley can achieve lower system cost, complexity, size, andweight than the prior art. It is also possible for the inventivepositioning device to have a scalable design that can be used to createsmaller or larger positioning devices, with correspondingly smaller orlarger payload capacities. As the payloads increase in size and weight,the belt or teeth must increase in width and tooth profile to keep upwith the weight increase. This leads to a thicker outer ring gearedsurface, and likely a larger gear diameter to increase the gearreduction ratio. As the turntable and belts scale up, the bearing loadhandling geometry will likely change from the single-rowed variants tothe dual and triple rowed variants to not only handle the additionalweight of larger payloads and a larger housing, but the rolling geometrymust also consider if the larger payloads require reduced torque oradded stiffness, such as when aiming long-range cameras with very tinyangular movements. Thus the 4-pt contact configuration is a great choicefor the smallest positioning device, with the single-row roller bearinga next best option where there aren't as high dynamic loads butstiffness is desired, with super-duplex angular bearings becoming theconfiguration of choice when size and cost are less of a concern thansuperior load handling and precision.

The beneficial improvements of the positioning device can be achieved byselecting either of the bearing configurations described, for anydiameter bearing. The variety of payloads; different load environments;and customer preferences for optimizing cost, weight, or other factorscreate too many variables to assign a particular bearing type to aspecific range of diameters; rather general recommendations and bestfits can be identified. The more important consideration is that theselected bearing configuration handle all types of loads, to at least amoderate degree, by itself. This permits a single bearing to replace apair of bearings, reducing cost and complexity, as well as preventingeventual failure of both bearings when a complementary paired bearingfails. While a low-profile thin-section bearing or bushing can be addedto supplement the single turntable bearing, with a light fit on theshaft to permit disassembly, the large turntable bearing alone canhandle all load vectors more reliably than prior art bearing designs.

Another benefit of the turntable drive is the gear rotation can beconsistently concentric. As with bearing installation, a pulley or gearmay not be seated sufficiently flat upon the shaft when press-fit, andthis error can double in magnitude when the pulley is press-fit onto abearing race and this bearing assembly is subsequently press-fit onto ashaft. This misalignment introduces a wobble or lop-sided rotation pathwhere a balanced, concentric rotation is desired for proper belttracking, gear mesh, and precision aiming of payloads. Such non-uniformmotion can cause misalignment of meshing gear or belt teeth, uneven belttension, and non-uniform torque output. In a precision aimingapplication, subtle inputs from the motors need predictable, repeatable,consistent output at the drive shaft. By flat-mounting the turntablebearing and hobbing the gear teeth onto the outer race, the drive'sconcentric motion is not jeopardized by press-fits and achieves moreconsistent, efficient motion.

In an embodiment, the pan bearing and the tilt bearing can be slew ringbearings or turntable bearings. The turntable bearing 391 is preciselymanufactured and may inherently have less play between the inner ring133 and the outer ring 137 than normal bearings. The turntable bearingsare a lower complexity, lower cost, smaller size and lower weightalternative to paired bearings and crossed-roller bearings which mayalso have very little play.

In an embodiment, it is an objective of the invention to view and tracktargets in excess of 5 km from the positioning device. This level ofaccuracy can be achieved with high pre-load bearings. A high pre-loadreduces the vibration, which can improve the aiming of devices such aslasers and video cameras at long range and prevent blur in video. Theinvention is also required to be very quiet to prevent surveillancetargets from realizing they are being targeted, and high pre-loadbearings reduce audible noise output. Pre-loading a bearing introduces apermanent thrust load to reduce give or play that results fromclearances between the internal components. Increasing pre-load has thebenefits of increasing the stiffness of the structure and the tendencyto displace under load and increasing rotational accuracy. The pre-loadalso has the benefits of reducing run-out, vibration, ball bearingskidding, and audible noise. The tilt shaft and the housing of thepositioning device may rotate at up to 1 rev/sec. At this speed, theprototype bearing's audible noise is only a faint, high frequency tonethat is not expected to be audible through the sealed enclosure. The lowspeeds and low duty cycle of the inventive positioning device will notgenerate the heat of a bearing running continuously, and the low speedsare not expected to generate vibration of any significance into thepayload devices. For these reasons the benefits of a high or evenmoderate pre-load are likely outweighed by the cost of the addedbreak-free torque. With higher pre-load, the bearing will be lesssensitive to minute motor impulses for long-range tracking.

When the bearings are placed under pre-load, there is some elasticdeformation of the bearings. One way to measure pre-load is throughelastic deformation; for example, in an embodiment, the pre-load elasticdeformation for the pan bearing and the tilt bearing can be about 0.0001to 0.0006 inch. A positive preload will prevent false brinelling fromoccurring which may lead to premature failure of the bearing. The panand tilt bearing preload is determined by the bearing manufacturer andmay be adjusted upon request before fabrication. In an embodiment, thepreload can be implemented by varying the size of the ball bearingsused. The preload can be determined by loading the bearing withundersized balls and measuring the clearance between the balls and theinner and/or outer ring. The undersized balls can then be removed andreplaced with larger balls to obtain the desired bearing preload. Theballs may have diameters that are sized in 0.0001 inch or smalleruniform increments. Thus, the proper ball diameter can be inserted intothe bearing to provide the desired preload. If the preload needs to bechanged, the balls can be removed from the bearing and replaced withdifferent sized balls.

The low pre-load can reduce the torque drag on the tilt shaft and panshaft such that very small movements may be made without any positionalerrors due to drag. In other embodiments, the replacement bearings withhigher preload values may be necessary if wobble or play is observed inthe tilt bearing or pan bearing. The wobble or play can be measuredusing cameras zoomed out at long range mounted on the positioningdevice. Another means for quantifying the pre-load is by strain which isa normalized measure of deformation representing the displacementbetween particles in the body relative to a reference length.

In a preferred embodiment, the bearings can have a large percentagecompliment of bearings; however, a larger compliment of bearings mayrequire a loading notch formed in the inner and/or outer ring. The notchin the inner and outer ring can be aligned to allow the balls to beplaced into the grooves of the inner and outer rings of the bearing.This loading notch may not be required for smaller percentage complimentbearings; for example, a bearing having up to a 50% compliment can beassembled without a loading notch; however, a 67% compliment bearing mayrequire a loading notch in order to install the balls into the bearingsand will have higher load capacity because of the additional balls. Inan embodiment, the balls and the inner and outer rings of the bearingmay be plated with a hard metal such as thin dense chrome (TDC) whichcan provide hard contact surfaces between the balls and the four pointcontact with the inner and outer rings.

The bearing can also include a ball separator that keeps the ballsevenly distributed around the bearing and is installed between the innerand outer rings. In an embodiment, the separator can be made of Delrinor any other similar lubricious material. There may not be a significantdifference in rotational resistance based upon the separator material;however, a single continuous separator which has a pitch that matchesthe bearing may have less rolling resistance than a segmented separatorhaving open ends. Approximately 90% of the rotational resistance in thebearing can be from the four point contact design and preload of thebearings, thus the separator may have may little effect on therotational drag.

Earlier has been detailed the need to align shafts and bearings toprevent preloaded bearings, prevent shafts from grinding in their bores,and permit precise positioning. While small embodiments have shortshafts that do not lead to intolerable misalignment, larger embodimentsin high-performance positioning applications may be effected. Adequatealignment for small embodiments can be achieved through controlledplanar tolerances on turntable bearing lands 166 and 168, similarlycontrolled flatness on mounting surfaces and bores, along with alignmentpins and keyways. Higher precision tolerances are required as the shaftmount points grow farther apart. To avoid excessive cost, a shaftcoupler can be used to mate shaft pieces.

Rotary shafts often have stepped diameters, flanges, gears, or otherfeatures that prevent installation through bearing bores and bulkheads;a point that has already been made by explaining the installationdirections of various shaft pieces. In most embodiments, each shaft isradially separated into two or more sections for assembly into thechassis/housing. Separate shaft pieces are often necessary wheremultiple bearings cannot be press-fit over the shaft in a singlepressing. The shaft pieces are often fastened together with bolts, setscrews, in-line pins, or integral clamping hubs. Where the shafts piecesmust be angularly aligned to ensure payloads aim to the same angle, setscrews, pins 138, and keyways are used. These additional matingstructures increase the size, weight, complexity, and cost of the shaft.The assembled shaft pieces are never as strong as a shaft made from asingle piece of material; bolts and keyways will fail from torque andshock loads that would otherwise be transmitted via a one-piece shaft.Angular, axial, and parallel misalignment will also increase as theshaft is broken into more pieces, even when taking great care andexpense to reduce tolerances and concentricity in the pieces. The addedcomplexity increases opportunities for design errors and assemblyerrors. An assembly technician's error, such as insufficiently torquinga bolt, or a high vibration environment can lead to loose connections orshaft failure. Shaft couplers are intermediary parts that mitigate theseproblems.

A shaft coupler mates two shaft ends with a stronger link than may beachievable with direct shaft mating. Two aluminum shaft ends can havesimple geometry, reducing cost, while the coupler can include the morecomplex mating features such as clamps, bolts, alignment pins, and setscrews. The coupler can be of a material stronger than the shafts, suchas a steel coupling for aluminum shafts, which can reduce the volume ofthe assembly by thinning the walls of clamps, keyways, and otherstress-handling features. Many shaft couplers also have features thatmitigate the significant problem of shaft misalignment.

When a shaft is penetrating two bulkheads, there is typically a need toalign the entrance point with the exit. There is often a bearing mountedto each bulkhead to support the shaft at two or more points, andmisalignment between these bearings can damage to the bearings. Infabrication techniques such as molding of composites or curing ofplastics, it may not be possible to control the final location of thebearing mounts within design parameters. Misalignment can also beintroduced by damage or dimensional errors in the housing and/or shafts.Types of misalignment include axial, parallel, and angular. Axialmisalignment statically pushes or pulls (compression or tension) theshaft between bearing mount points, imposing an axial pre-load onstructures such as tightly press-fit bearings. In the case ofdeep-groove radial aka Conrad bearings paired on shafts of prior art, animproper axial pre-load can greatly reduce the radial load capacity ofthe bearing. Parallel misalignment can result from poor concentricity inthe shaft or where a pair of bearing mounting bores are not perfectlystraight; one hole is shifted off axis. It can impose a radial pre-loadwhich can cause inconsistent rotation and reduced radial load andcombined load capacity. Angular misalignment can occur where bearingmounting bores or mating shaft ends are not perfectly parallel, whetherpress-fit tight or loose. It imposes a moment pre-load and can reducemoment load and combined load capacity of bearings. Each of theseimperfections pre-loads the shaft bearings out of intended designparameters, resulting in negative changes such as: increased bearingfriction, increased starting torque, increased false brinneling in highvibration environments, reduced maximum speed rating, and reduced loadcapacity. Mitigating the misalignment problem can be very expensive,usually by reducing the machining tolerances of all shaft and chassisparts, possibly upgrading to a higher ball grade, and spending more timeand money on the assembly process.

Other features such as position sensors and gears require the shaftposition be precise, accurate, repeatable, and robust under the designedoperating environment, so effort and expense is warranted to mitigateshaft misalignment. Rather than throw money at the problem, designerscan adopt a shaft coupler with a flexture that deforms to neutralizemisalignments while also absorbing shocks and damping vibration.

The preferred shaft coupler type for integration into the inventivedevice is a beam type a.k.a. ‘helical’ coupler. This type employs anintegral flexture where the material in a central section is spiral cutinto a helical coil; it is single piece whereas other types sandwich aseparate rubber flex disc. The thin coil structure remains rigid yet hassome spring action to accept and offset a few degrees of angularmisalignment, and offset a few thousandths of an inch in parallel andaxial misalignment. The helical structure can be made more flexible topermit sloppier machining tolerances and assembly precision, but thiscomes at a cost of reduced rigidity, torque capacity, and fatiguestrength. In the case of the inventive device where payloads attached tothe shafts must remain closely in alignment with each otherrotationally, and machining tolerances can be reasonably kept to+/−0.001-0.002″ without excessive cost, a somewhat rigid flexture canabsorb the expected small misalignments without the increased fatiguefailure risk associated with thinner coils.

Such a coupler can be useful on a tilting embodiment or pan-thru-shaftembodiment where misalignment between two bearings is possible. Withreference to FIG. 23, helical shaft coupler 188 mates tilt shaft pieces186 and 187. The ends of the tilt shaft pieces can have keyways to alignwith keys in the coupler to maintain rotational alignment between theshaft pieces. Clamps at each end of the coupler can tighten around theends of each shaft to transfer axial and rotational loads. Between thecoupler clamps can be a spring-like bellows that can flex to absorb thestatic loads of a few degrees of misalignment in the shafts 186 and 187,while this bellows can also absorb shock and damp vibration travel alongthe tilt shaft. The coupler and its integral flexture are comparablydelicate to the rigid shafts, and the flexture may be the weakest linkin a given shaft assembly, especially from fatigue flexing of thebellows, thus it's likely the first component to fail. Ideally coupler188 can be sized to fail at a load threshold slightly below that whichwould damage attached bearings, acting much as a crumble zone,sacrificial link, or mechanical fuse to isolate the bearings and shaftsfrom damage. Such coupler can be 7075-T6 aluminum, hardened steel,beryllium, or other high strength material to tune fatigue life anddesign the failure point to protect the shafts. While a coupler is asmall bolt-on part, generally inexpensive, bearings and custom shaftsare comparably expensive and require more time and cost to diss-assemblethe positioning device and repair. Thus a shaft coupler increases systemperformance, with reduced or equivalent component costs, with additionalcost savings over the life of the product via cheaper repairs.

An uncommon modification to the shaft coupler is a flange for angularposition sensing. This flange can include markings, magnets, or otherfeatures that can be read by a read head mounted to the housing. Thisfeature improves the true position of the features compared to aseparate flange or encoder wheel which is fastened to the shaft, such astilt shaft position disc 147 in FIG. 22, and this integration candecrease cost, complexity, installation labor, and increase reliability.

The most common drive employed by pan-tilts has been the worm geardrive, and geared turntable bearings and slew rings are predominantlygeared for spur gears. While embodiments of the invention can adopt spurgears attached to the motor rotors or a worm gear driving a turntablebearing, geared drives are subject to backlash and tooth damage underthe vibration and shocks of mobile deployed equipment. In such anenvironment, it is preferable to adopt a belt drive.

While position precision, accuracy, and repeatability have been theprimary optimizations sought in recent geared and belted drives, mobiledeployment of positioners have illuminated the fact that accelerationsand other perturbations such as a vehicle driving over potholes willdemand more torque to stabilize the shaft position than a stableplatform. Thus a mobile positioner must derate its load capacity formoving, dynamic operation upon boats, vehicles, aircraft, or othermobile platforms to account for the external accelerations. Prior artrecognize the effect of accelerations by derating their products'advertised torque capacity for on-the-go operation. The currentinvention promises to pioneer belt-driven positioning into territoryentrenched with complacent, heavy, gear-driven designs by offeringgreater torque to weight ratios and torque to volume ratios, belts thatresist walking, tooth profiles that offer unprecedented torque in aposition registration application, belt retention features, a lowfriction power train, environmental sealing that prevents moisture anddebris from corroding bearings and settling on pulley surfaces, andmotors which have fast response for stabilizing the shafts againstexternal, dynamic accelerations.

Recent advances in belt technology have doubled torque capacity for abelt having the same width and pitch; for example, standard curvilinearteeth profiles can have far more torque capacity than trapezoidal shapedteeth, but may not be suitable for precision positioning. Thus,trapezoidal teeth profiles may be better than standard curvilinear teethfor the inventive positioning device; however, in other embodiments,modified curvilinear teeth profiles have the performance benefits ofboth trapezoidal and standard curvilinear. Modified curvilinear teethcan provide double the torque capacity while providing greatly improvedposition registration traits compared to standard curvilinear teeth.Modified curvilinear in comparison to trapezoidal profiles can becharacterized as sacrificing a little position precision for a lot oftorque capacity. These belt characteristics have nearly eliminatedposition error and backlash from belt elongation as disclosed by U.S.Pat. No. 7,824,284, “Power Transmission Belt And Cord Adhesive SystemAnd Adhesion Method” and US patent Publication No. 2011/0005675 A1entitled, “Power Transmission Belt And Cord Adhesive System And AdhesionMethod” which are both hereby incorporated by reference.

Using fiberglass or carbon as tension fibers within the belts reducesthe belt stretching and allows the belt tension to hold consistentcircumference over time and operation. A properly tensioned beltmaintains torque capacity, prevents ratcheting, prevents belt dustcontamination, and the lack of torsional wind-up makes very precisemotor inputs result in very precise pan or tilt shaft movements. Thebelt construction methods with fiber cords have also alleviated thepropensity of belts to walk off track by introducing twists into thecords. Most synchronous belts are made with both “S” clockwise and “Z”counter-clockwise twist cord to minimize belt tracking forces on thepulley flanges.

The belts are flat and can include molded teeth on the belt and matinggrooves of the outer diameter of the bearings and pan motor gear andtilt motor gear. The positive engagement of the teeth with the bearingsand the motor gears produces a smooth rolling manner with low friction.This positive engagement results in exact shaft synchronization,elimination of slippage and speed loss and synchronous operation atspeeds higher than most chain drives. The synchronous belt drive is nota friction device. It is a positive engagement drive that is dependentupon the meshing of the belt teeth with the pulley grooves. Synchronousbelts are up to 98% efficient in transmitting power. Synchronous beltsoffer an efficiency of about 98% and maintain that efficiency. Theno-slip characteristic provides exact synchronization between a powersource and a driven unit. Synchronous belt drives are extremely usefulin applications where indexing, positioning, or a constant speed ratiois required. Belts have many advantages over gears or chain drives.Belts are quieter in their operation, less expensive and more efficientand lighter than a gear or chain system. Also, timing belts do notrequire lubrication, which is essential with a timing chain or gears.The belts can have trapezoid shaped teeth or modified curvilinearprofile teeth that engage corresponding trapezoid or curvilinear teethon the outer diameter of the bearings or motor gears.

Until these advances in belt technology, belt drives were regarded asprone to losing position from ratcheting, requiring field servicing fromthe belt walking off track, and poorly suited for drives requiring bothposition registration and high torque.

With reference to FIG. 35, a top plan view of an embodiment 401 of thepositioning device illustrates tilt belt 116 wrapping around both tiltmotor 114 and tilt shaft gear 131. The inner surface of the tilt belt116 and the outer surface of the tilt shaft gear 131 can havecorresponding teeth to prevent slipping between the tilt belt 116 andthe tilt shaft gear 131. With reference to FIG. 34, a front crosssection view of device 401 has sectioned tilt belt 116 and exposed frontview of the tilt motor and tilt pulley not visible in other frontsectionals disclosed. The inner surface of the tilt belt 116 and theouter surface of the tilt motor gear 114 can have corresponding teeth toprevent slipping between the tilt belt 116 and the motor gear 114. Thepan shaft can have the same component arrangement, with pan motor 102having a pan motor gear 104 that is coupled to the outer ring 137 of thepan bearing 127 with a pan belt 106. The inner surface of the pan belt106 and the outer surface of the outer ring 137 can have correspondingteeth to prevent slipping between the pan belt 106 and the outer ring137.

In a position registration device such as the claimed positioningdevice, accurate and repeatable tension must be applied to the belt,cable, or chain linkage to operate with the precision required forposition registration applications. If a linkage is over tensioned, itmay damage tensile reinforcement in the belt, increase wear, andpossibly shear a tooth. Over tensioning may also overload other drivecomponents such as bearings, shafts, and motors. Motor rotors rotate onbearings and have limited radial load capacity, excess tension can warpthe rotor assembly and lead to eccentric rotation and inconsistenttorque. In the case of under-tensioning, there may be reduced belt wrap,fewer teeth engaged, lower torque capacity, a ratcheting of the belt asteeth loosely slip out of their grooves. Ratcheting wears the belt teethand causes the system to lose track of the motor and shaft rotaryposition.

To install and tension a belt, cable, or roller chain, prior art hasmounted motors to plates which are adjusted to tension the belt, thenlocked down. Typically the motor mount plate has a slot which alignswith a threaded hole in the positioning device chassis, such slot sizedto permit the plate and motor to move radially towards the shaft pulleyfor belt wrapping, then move radially away from the pulley to removeslack.

From a belt manufacturer's Precision Timing Belt Technical Manual:

“The adjust and lock-down method applies a force directly to anadjustable input or output shaft of the system . . . . Similar to thespring-loaded pulley/idler method, a vector force analysis isrecommended to ensure proper tensioning. Likewise, if the adjustment ismade about a pivot point, be sure to calculate the moment developed. Theload can be applied to the shaft in a variety of ways. Two commonly usedmethods are to attach either a static weight or spring scale to theadjustable shaft. Once the drive has been set, the sonic tension methodis a common way to determine belt tension . . . . This method uses thesound waves generated by “plucking” a single span of the belt. Amicrophone is held just above the belt in the middle of the plucked spanto measure frequency. As installed tension changes, the frequencychanges. Through applying known installed loads to the belt, a graph isdeveloped correlating frequency to tension. Once the frequency valuesare determined, belt tension can be adjusted to the proper value.”

Prior art has required technicians hand-tighten motors on the adjustableplates, usually resulting in inconsistent tension that createsinconsistent motion and torque capacity between products of the samemodel. Tooling can be developed to create a more consistent deflection,but removable tooling may not fit inside a tightly packed housing, norwill tooling address loss of tension after the device has left thefactory. The motor mount plates are bolted down to hold position, withonly the friction of the bolt held preventing the tensioned belt/chainfrom pulling the motor out of position. In the high shock and vibrationenvironments of the positioning device's use, these bolts may loosen, orsimply fail to prevent sliding. In newer belts with inelastic tensionstrands such as fiberglass, the elongation at full tension may be only0.1-0.2% of the belt length in a small robot, so even a tiny slip candrastically reduce the grip of the belt and torque capacity of thedrive.

One option to position the belt and maintain the position in the fieldis a cam pusher, but this inflexible displacement mechanism isintolerant of manufacturing inconsistencies, installation errors, andmay apply a moment load into the motor plate upon engagement. Anothermethod to tension a belt is an adjustable idler pulley paired with afixed motor. The idler pulley can be manually positioned to adjustablydeflect the belt a known-good-distance, and be locked into place. Anoutside idler pulley can also increase belt wrap at the motor drivepulley, increasing torque capacity, but this pulley adds volume, weight,complexity, and cost to the design. This idler solution can suffer thesame inaccuracy and inconsistencies of hand-tightening an adjustablemotor plate, and the idler mount may also suffer a failure from relyingon bolt head friction to hold its position. While vibration may loosenbolt threads, shocks are more likely to exceed bolt head friction. Atorsion member such as a spring can be used to apply a constant force ofvariable magnitude to vary the deflection of the idler. When the deviceexperiences a shock, the spring can absorb and dampen belt shocks thatcould loosen the bolt heads; however, this variable tension can causevariable torque during shocks. A precision positioning device requiresconsistent torque during high shock events to maintain operation throughall conditions.

With reference to FIG. 48, a front sectional view of a belt driveemploys an adjust and lock-down motor assembly enhanced with a geartrack assembly to incrementally tension a belt and retain tension undershock and vibration. A pan motor 102 is rigidly attached to a slidingmotor mount plate 282. The plate can adjustably slide across a plate,shelf, or rail stand-offs 669 rigidly attached to the floor of housing111. The housing rails 669 and motor plate 282 thickness are sized toalign a motor gear 104 parallel and aligned to a shaft gear, with a belt106 transferring power between the gears. The housing rails 669 caninclude at least two mounting points, such as threaded inserts, to lockdown the motor plate 282. The motor plate can have slots overlappingwith the threaded mount points to permit fasteners to be partiallythreaded into the rails 669, with the motor plate then adjusting withinthe constraints of the slots. The screws on the motor mount plate 282with slots constrain yaw, pitch, roll, and Y and Z translation. There isonly one degree of freedom that is left which is X, the motion that theslots allow a technician to move to tighten the belts. As the motoradjustment plate 282 moves radially away from the rotary shaft, a lineargear track 685 rigidly attached to the motor mount plate 282 can engagewith a pawl 680 rigidly attached to the housing 111, or vice versa. Ashoulder screw 684 fastened into the housing can contain a torsionalspring 682 and the pawl 680, the pawl and spring rotating about theshoulder screw. In an embodiment, the shoulder screw 684 can be an 18-8stainless steel precision slotted shoulder screw with ⅛″ shoulderdiameter and ⅜″ shoulder length, with a 4-40 thread. The torsion spring682 pushes the pawl 680, applying a constant force to keep the tip ofthe pawl in contact with the gear track 685. As the gear track movespast the pawl, the pawl catches and engages teeth in the gear track toprevent motion in the opposite direction. The gear teeth can be angledto allow the pawl 680 to glide over them in one direction and lock inthe other direction. With each click of the pawl, the motor mount 282discretely increments tension onto the belt 106. Because the beltsdescribed have very little elastic deformation, the gear and pawlengagement may be a narrow range of motion, and the teeth of gear track685 and the tip of pawl 680 can be very fine to make very smallincrements in the tension of belt 106. Technicians can achieve veryrepeatable tensions in the belt 106 by incrementing discretely. Toprevent damage to fine teeth of linear gear 685 and the pawl 680, thesefeatures can be materials such as titanium, tool steel, or other veryhard, wear resistant material. A measurement tool such as a sonictension meter can be used to verify proper tension, without a human handholding down the motor plate 282; one can measure a few times and adjustaccordingly before the fasteners are fully tightened to lock the motor102 into position. The gear track assembly and bolt heads can then worktogether to maintain tension throughout high vibration and shock. Todisengage the gear 685 and pawl 680, there can be a projecting feature,a pawl lock pin 681, that sticks up and can be pulled to move the pawl680 away from the gear track, or the pawl can have a hole in it for atool to insert and pull away the pawl from the gear 685. This feature681 will allow release of the pawl 680 to un-tension the belt 106.

With reference to FIG. 59, in another embodiment of an adjustable motormount, a screw 671 can be turned to drive a wedge 670 between thehousing and the tilt motor mount plate 115, with a similar screw-wedgearrangement for the pan motor. U.S. Pat. No. 4,921,378 describes anarrangement of wedges that are adjusted to precisely and firmly clampfixtures and metal stock to be precisely CNC machined. In thisapplication, a vise jaw 673 presses against the housing 111 via anabutment on pan bearing flange 129 while a second jaw 673 is opposed bythe tension of the pan belt 106 constraining the motor 102 and attachedmount plate 282. As the screw 671 is tightened, the wedge 670 is drivenbetween jaws 673. As the jaws spread, the motor mount plate 282 isradial displaced. The ends of vise jaws 673 can have rough, serratedsurfaces to grip the housing and motor mount plate 282. To anchor thejaws into a semi-permanent place, the jaws can have holes for fasteners.With reference to FIGS. 51-53 is a wedge vise with no mount points foreither jaw 673, while FIGS. 54-67 include a pair of fasteners to fix onejaw 673. Lower profile jaw anchors can be alignment pins, a dovetail,tongue-in-groove, or other keying. As with all fasteners employed in thepositioning device, the screw 671 can have thread-locking compoundapplied to prevent loosening in the field, preferably a non-permanentformula to permit error correction and maintenance.

With reference to FIG. 52, a wedge 670 is angled on a left and rightside to equally displace a pair of jaws 673. This is effective in a CNCjig where a threaded hole for screw 671 can be precisely located at themidpoint between two parts, but a tensioning a belt is not aspredictable. Should one jaw 673 make contact with a surface before theother jaw, continued screwing of bolt 671 can impart a moment load intothe threads. With reference to FIG. 56, a left side of the wedge 670 cabbe angled so only the left jaw 673 will be displaced leftward, while thesecond jaw can not be angled. Because the right side of the wedge isstraight, there is no wedge action applying a sideways force. When theleft jaw 673 makes contact with a surface, it will induce a sidewaysload towards the right, but the right-anchored jaw 673 serves as abackstop to equalize force on the threads of bolt 671. With reference toFIG. 58, the angled jaws 673 have been integrated into the pan bearingflange 129 and motor mount plates 115 and 282. With reference to FIG.60, a partial side view sectional of the positioning device 101illustrates a tilting assembly where turning of bolt 671 can lower wedge670. A mating slope on tilt motor mount 115 slides the motor radiallyaway from the tilt axis as the wedge forces itself downward. An abutmenton pan bearing flange 129 can serves as a backstop to prevent theopposing force of the tilt motor mount from side-loading the bolt 671and misaligning the threads. As the bolt is tightened, the tilt motormount 115 and attached tilt motor 112 move away from the tilt axis,incrementally taking out the slack in tilt belt 116. A non-permanentthread-locking compound can be applied to the motor mount screws andwedge bolt 671 before tensioning to prevent shock and vibration fromreleasing the fixed position. With one or more of the described motoradjustment features, a positioning device with a tensioned power traincan be precisely tensioned and hold that tension throughout roughservice in the field.

With reference to FIG. 30, in order to protect the internal componentswithin the housing 111 dynamic seals 152, static seals 156, and airvalve 150 can be used to isolate the internal components from theexternal environment. The seals and internal pressurization can providean air and liquid fluid barrier which prevents gas, liquids and solidcontaminants, such as dust, from entering or remaining within thehousing 111.

Solid contaminants (“dust”) within the housing 111 can damageelectronics, obstruct optical devices, and gum-up the smooth motion ofthe positioning drive mechanisms. Dust can increase friction andincrease running and break-free torque for the rotating mechanisms, andcan eventually lead to drive mechanism failure. These dust particles canwork their way into lubricants within moving components such as motorsand bearings, drying them out and creating a viscous, abrasive grit.This can reduce the grease's heat transfer ability, permitting hot spotsand thermal expansion in precision moving parts. The particles createmini speed bumps between bearing elements where smooth, gliding motionis required, leading to wear of the precision polished surfaces of thebearing elements. These undesirable effects would be observed in thepositioning device 301 as increased vibration, slip-stick chatter, andtorque drag.

While an objective of the invention is to sufficiently protect allenclosed components from environmental threats, bearings 391 and 144 caninclude face seals as a second line of defense from exposure to fluids,gas and dust. With reference to FIG. 42, the balls 135 and raceways ofbearing 391 can be covered and protected by face seals 160. The faceseals 160 can be installed over the raceways as the primary seal againstcontaminants. The inner diameter and the outer diameter of the faceseals 160 can fit and slide within grooves 397 formed in the inner ring133 and the outer ring 137 and the face seals 160 can also be recessedrelative to the planar surfaces of the inner ring 133 and the outer ring137. These face seals 160 can provide additional protection for thebearings 135 from exposure to fluids, gas and dust. While a sealedenclosure may provide adequate protection, the face seals 160 can alsoprotect the bearing during shipping and assembly. Face seals 160 can bemade of various materials including: Buna-N nitrile, a black rubber orpolytetrafluoroethylene (“PTFE”). Because of its lubricious properties,PTFE can permit the bearings to survive a wide range of chemicals andextreme environments without inducing excessive drag and slip-stickchatter associated with high stiction drives of prior art.

Dust on the teeth of meshing spur or worm gears attack with similarresults of wear, vibration, and frictional torque loss; additionally theincreased wear on teeth accelerates development of backlash in thedrive. In a belt drive, dust on teeth of belts and pulleys can reducethe mechanical grip, reducing the torque output achievable before beltratcheting/slip occurs. Dust can also blanket or insulate the internalelectronic components which can lead to overheating and failure. Thepositioning device can also include optical encoders and limit switcheswhich may not operate properly if covered with dust. Any opticalpayloads integrated into the housing will also be susceptible to dustdepositing on optical surfaces, reducing image quality or lasertransmission efficiency.

With reference to FIG. 23, fluids and condensing gasses (‘moisture’)that ingress into the housing 111 via actions such as full immersion inwater, exposure to rain, humid air, or out gassing of etchants trappedwithin the enclosed circuit boards can short-circuit electronics,condense onto optical surfaces, corrode metals, breed fungus, and damagethe rotating mechanisms. Moisture is of particular concern in a deviceutilizing a variety of materials in contact with each other to optimizeweight and strength—such as carbon fiber and titanium or aluminum andsteel, pairs which have a high galvanic potential between themselves—asthe presence of moisture is a catalyst for galvanic corrosion. Corrosionin fasteners can seize joints such that they hamper servicing of theequipment, with snapped-off bolts resulting in permanent damage andextensive repair efforts. The positioning device can embed threadedfasteners such as Keenserts and Helicoils to reduce the impact ofcorrosion at fastener joints, but other components would still besusceptible. Bearing components have highly polished precision surfaceareas that are detrimentally affected by corrosion caused by moisture.Corrosion can seize up motion, pit the smooth surfaces resulting in morevibration of the rotating components and material loss due to corrosioncan reduce the load capacity of the bearings. Moisture on the teeth ofthe belts can reduce the mechanical grip with mating gears. Water canalso short-circuit or corrode the internal electronics and condensationinterferes with optical encoders, limit switches, and fogs opticallenses of payloads integral with the housing 111.

Round static seals have been used in prior art to seal gaps betweenshafts and the housing but these elastomer rings do not seal againstboth surfaces; the elastomer wears rapidly, the rings coil and extrudefrom their groove, and the seals often fail to contain even light fluidand gas pressures. The positioning device 101 includes one or moreshafts which move in intermittent, dynamic rotations, and utilizedynamic rotary shaft seals 152 to achieve adequate protection from theenvironment.

The dynamic seals 152 can be installed between moving parts to limitingress of dust and moisture; for example, a dynamic seal 152 can beinstalled between the housing 111 and the pan shaft 125, and dynamicseals 152 can also be installed around the tilt shaft 105 and thehousing 111. The top of the pan shaft 125 fits within a recessed area ofthe housing 111 and the seal 152 is around the pan shaft 125 close tothe bottom of the housing 111. The seals 152 are also around the tiltshaft 105 just inside both the first side 121 and the second side 123 ofthe housing 111.

In FIGS. 5, 6, 11, 23, 34, the pan shaft 125 can be substantially thesame and the seal 152 is also identical or substantially the same. InFIG. 5, the seal 152 is in a recessed area in the bottom of the housing111, and a larger diameter step in the shaft 125 can narrow the entranceto the seal gland to shield the seal 152 from direct debris strikes andblast impulses. In FIGS. 12-14, a small diameter pan shaft 225 is usedand the seal 152 can be the same as those used on the larger diameterpan shaft 125 except for being constricted in diameter to maintaincontact with the shaft 225. In FIG. 13, pan shaft 225 does not have astep or flange to shield the sealing gland entrance but an annularflange 155 can be attached to the entrance of the gland to provide ashield. Similarly, with reference to FIG. 22, the seal 152 on the secondside 123 of the housing is identical to the seal 152 in FIG. 23, exceptit has been radially expanded to seal the larger diameter of the tiltshaft 105 of FIG. 23. Cost savings and inventory efficiencies can berealized by sizing tilt shaft 105 diameters in contact with the seals152 to be identical, resulting in identical seals 152, thus a singlepart number for seal 152.

Dust and moisture from the external environment can often attempt toingress housing 111 under high force such as hurricane winds, pressurewasher jets, sand storms, or explosions. With reference to FIG. 47, adynamic rotary shaft seal is illustrated in a sealing gland. The dynamicseal 152 has a “C” shape with the open portion of the seal facing theambient volume and the closed portion facing the interior of thehousings. In this configuration, if the ambient pressure is higher thanthe internal pressure, such as with hurricane-force winds or battlefieldexplosions, the ambient pressure will tend to expand the diameter of theseals 152. In contrast, if the internal pressure is higher than theambient pressure, the seal 152 can be compressed and the internal gasescan escape before the static seals extrude or the housing explodes.Where the positioning device 101 is exposed to low pressures such astroughs of blast waves or when mounted to an aerial vehicle at highaltitudes, dynamic seals 152 can be duplex seals with a “)(”orientation. Duplex seals include an internal facing “C” seal to keeppressure inside the housing. In an embodiment, the internal volume ofthe seals 152 can be filled with a spring or other mechanical device 252that excerpts an inner diameter inward force on the shaft to improve thesealing of the seals 152; however, the added force on the seals 152 canalso produce rotational friction and vibration of slip-stick chatter.The rotational friction should not be high enough to cause positioningerrors in the pan shaft 125 or the tilt shaft 105. The seals 152 can bePTFE lip seals, o-rings, gaskets, seals or other mechanisms whichprevent gas and particles from entering or exiting the housing.

With reference to FIG. 30, the housing 311 can also include static sealswhich can be o-rings, gaskets, seals or other mechanisms which preventgas and particles from entering or exiting the housing 111. Static seals156 can be installed between faying edges of mating parts to preventpassage of environmental hazards. Common static seals can fail throughgas permeability of the elastomer, chemical exposure, weathering,abrasion, torsional coiling inside the groove, and loss of compressiondue to loose fasteners or bowing of insufficiently stiff gland walls.Design errors can also lead to seal failure, such as faying edges thatare insufficiently thick and stiff, insufficiently flat, or have asurface finish that permits gas molecules to leak past micro-fissuresthat pass across the seal contact zone with the groove. As static sealsare points of failure in a sealed volume, an inventive feature of thepositioning device is a simplified, monocoque housing with reduced seamlength to reduce points of static seal failure. In the illustratedembodiment, device enclosure 301 may only have a top cover 313 and amain housing piece 311. Thus, the only static seal required for thehousing shell 311 is for the top cover 313. The positioning device 301can use at least five static o-ring seals including a first seal betweenthe housing 311 and cover 113 at the top, a second seal for an airpressurization valve 150 in the pan shaft, a third seal for theelectrical connector 141 on the pan shaft, and backup o-ring seals onshaft mount brackets 128 and 145 of the tilt shaft 105. The backupo-rings in the shaft mounts can prevent leakage from gasses that hit thelip seal and expand outward, trying to pass between the housing'sinterior wall and the shaft mount brackets bolted into the wall. Cast ormolded construction which can more easily integrate or embed the tiltshaft mount brackets 128 and 145 into the walls than milled fabrication,such cast or molded housings can also adopt exterior dynamic seal glandslike the pan shaft 225 sealing gland to eliminate the need for internalbackup o-rings on the mounts, thereby reducing ingress paths to onlythree o-rings and thus improving sealing performance further. Withreference to FIG. 29, device 201 would not need the backup o-rings inthe brackets as the dynamic seals are exterior to the housing. In otherembodiments, the static seals can be gaskets, elastomer rings or anyother suitable sealing mechanisms. This design simplifies theconstruction and sealing of the positioning device and creates a housing211 that is more robust against environmental threats than other designsthat require more connected housing components.

To counteract external forces of pressurized contaminants and airattempting to blast their way into the protected interior, the housing211 can be pressurized with a conditioned gas through air valve 150. Thepositive pressure of the internal gas can provide an opposing force tocounter exterior pressures which threaten to extrude dynamic seals 152and static seals 156, which can result in failure of the sealing system.The shaft seals 152 and static seals 156 can hold the conditioned gasinside as well as keep the ambient gas and particles outside the housing211, with duplex dynamic seals preferable to contain the internalpressurization when the positioning device 201 is deployed in lowpressure environments. In the instance of a defective, leaky dynamic orstatic seal, the positive internal pressure will leak out theconditioned internal gas before contaminant laden external air can leakin. The housings can be pressurized to about 16-20 psi absolute inland-based deployments, and in preferred embodiments, the internal gasdoes not leak out. In other embodiments, a higher pressure within thehousing 211 may not lead to gas egress, if the seals are duplex and/orspring loaded to physically compress the seal against the shaft—whichcan have the drawback of added torque drag. The seals 152 can be coveredwith a lubricant so that the tilt shafts 105 and the pan shafts 125rotate smoothly against the seals 152 without damaging the seals 152.The dynamic seals 152 can also be made of a lubricious material such asa wear-optimized PTFE based polymer blend which can rub off toself-lubricate the moving contact areas.

Dust and moisture can also be introduced into the housing 211 duringmanufacturing assembly and routine maintenance. In addition to the airmass sealed inside the enclosure when cover 113 is fastened down to sealthe fully assembled unit, the internal devices and components containlatent moisture within their materials. Moisture can be trapped betweenlayers of circuit boards including the motor electronics, any onboardpayloads, the internal DC/DC converter 118, enclosed controller 574, orother electronic systems. The latent moisture from circuit boards,plastics, wires, and other components can even exceed the humiditystored in the air mass sealed within the enclosure 111, so simplyfilling the unit with dry air may not remove sufficient moisture to lastan acceptable product lifetime. While a clean room assembly environmentcan prevent some contamination at the factory floor, it is an expensivemeasure and cannot be practically duplicated for field servicing.Preferably, the housing 211 can be purged before pressurizing the sealedunit with gas, and the purging and pressurizing gas can be a dry, inertgas such as nitrogen. The purging and filling can occur through airvalve 150 located on pan shaft 125, or the air valve can be located onhousing 211 or cover 113 with the drawback of the valve's mass burdeningthe pan motor with additional rotational mass that is otherwise not seenwhen the valve is on the fixed pan shaft base. A purging process such asthe Brownell Method of nitrogen enriched purging can be used to extractmoisture from the enclosed air and any latent moisture within materialsof components such as circuit board etchants trapped between boardlayers. The remaining conditioned gas sealed within the enclosure 211can have many benefits: far fewer particulate contaminants such as dust;a reduction in potential for corrosion; a lower dew point to preventcondensation and optical fogging; and reduced static electricity. Thegas may be pressurized to improve the sealing performance of the staticseals 156 and dynamic seals 152.

In addition to dust and moisture, electromagnetic hazards in theexternal environment can ingress the housing 211 to disrupt or destroyenclosed electronics, melt or vaporize mechanical components, orelectrocute service technicians. Hazards can include: power faults,lightning, electrostatic discharge, electromagnetic pulse, navalshipboard degaussing charges, and radiated energy such as radar anddirected energy weapons. Electronics enclosed within the housing canalso be hazardous emitters of EMI/RFI that can escape through seams andpenetrations to interfere with external equipment such as communicationstransceivers. This internal energy can energize the housing shell piecessuch that they radiate as a dipole antenna if not electrically bonded. Astrategy employed to mitigate both ingress and egress of electromagneticenergy can be generalized as minimization of seams and penetrations withelectrical bonding between housing pieces, yet these design guidelinesare at odds with some common practices in design optimization formanufacturing which dictate small machines be broken into many parts toenable easy access for human hands and tools to assemble and service thedevice rapidly. The inventive device addresses this challenge withoutcompromise via embracing the simplified housing 211 and cover113—yielding a two-piece shell where prior art is more commonly three ormore assembled pieces with many seams, penetrations, and radiatingantenna—yet access for assembly and maintenance remains easy due to thecomponent integration and lack of press-fits in turntable bearings 131and 127. With a minimized total seam length, the shields in thedifferent shell pieces can be more easily electrically coupled together.The shielding can be an electrically conductive material or mesh ofelectrically conductive material. Electrical bonding between seals atfaying surfaces of components can use conductive static seals such aselastomer o-rings doped with metallic particles or carbon nanotubes. Bysurrounding the internal components with the conductive material ormesh, a “Faraday Cage” can be formed which can protect the internalelectrical and electronic components from static and non-static electricfields. This shielding can protect the internal components in the eventthat the positioning device is exposed to lightning, radio waves andelectromagnetic radiation, while also protecting exterior devices fromEMI generated by the positioning device 201. While this high degree ofshielding is uncommon in prior art, it is becoming a mandatoryrequirement in newly fielded defense and homeland security equipment viastandards such as MIL-STD-461G.

Because dust, moisture, and electromagnetic energy can be so hazardousto the positioning device, an enclosure with a minimum of entry pointshas been devised, and the necessary seams and openings have been pluggedwith dynamic seals 152 and static seals 156. In FIG. 23, housing 111 canbe a contiguous shell will only a cover 113 and one or two holes fortilt shaft 105. The positioning device can have a housing 111 having aminimal total length of seams. In a simple form, the housing 111 mayhave a bottom and four sides 121, 122, 123, 124 that are all fabricatedout of a single piece of material. The pan shaft 125 can extend througha hole the bottom of the housing 111 and the tilt shaft can extendthrough a hole or holes in the sides of the housing 111. All internalcomponents can be installed through the top opening and shaft bores.This monocoque construction minimizes the number and total length ofstatic seals required by the housing 111, which reduces points whereenvironmental hazards and radiated electromagnetic noise may leak.Pressurization and purging will be more effective with an enclosure withfewer leak points, and the pressurized unit can be expected to operatefor a longer duration before the positive internal pressure inevitablyleaks out. By minimizing the number of components, the housing 111 ofthe positioning system 101 can be stronger and have fewer seams andseals through which environmental threats can enter or exit the housing111. This design simplifies the construction and sealing of thepositioning device and creates a housing 111 that is more robust thanother designs that require more connected housing components.

Another benefit of the integrated, simplified housing of the inventivepositioning devices is that the housing 111 can have enhanced resistanceto mechanical vibration, shocks, and impacts. In an embodiment, thefirst side 121, second side 123, third side 122 and fourth side 124 areall fabricated from the same piece of material or are otherwise asingle, contiguous structure. The positioning device can have amonocoque construction where the housing 111 provides the externalsurfaces as well as the load bearing structure. Enclosures constructedof various pieces fastened together may not efficiently channelvibration between mating pieces and can set up unpredictable resonancescaused by indirect load paths and internal shockwave reflections atfaying surfaces. Mating joints are also subject to fatigue failurearound fasteners and loosing of the fasteners. Mechanical shocks andimpacts must be channeled from any contact point, including payloads,into kinetic sinks to dissipate the shock, and the kinetic path must beminimized and channeled through components designed to handleforeseeable shock loads. Enclosures fabricated from multiple pieces candeform or crack their joints under high shock loads, and the devicetends to absorb much of the energy rather than dissipate it into akinetic sink or channel it into the base structure to which it may bemounted. Because the monocoque housing has a single outer shell piece towhich the shaft turntable bearings are mounted, shock loads have shortkinetic paths to dissipate into the strong housing shell or channel intothe mounting base. A housing constructed of composites, plastic, orberyllium alloys may be superior in dampening shock and vibrationwithout the permanent deformation that can occur in malleable materialssuch as aluminum. This monocoque housing 111 design may create a greatchallenge for assembly, and may not be possible to assemble without theadoption of the mounting-holed turntable bearings, obstruction-freedrop-down installation afforded by vertical or outward drafted interiorwalls, removable tilt shaft mounts, and a well orchestrated assemblyprocedure. With reference to FIG. 10, integrating pan bearing flange 129into the floor of housing 111 can produce an even greater level ofintegration and structural rigidity as long as a carefully plannedassembly procedure is choreographed. The positioning device 101 can beespecially shock and vibration resistant when the integral housing 111is paired with the shock and vibration resistant motor mounts previouslydisclosed.

Yet another valuable benefit of the simplified housing is an easier,feasible transition from fabrication of milled metal construction tocast or molded construction. It is common in the field of the inventionto initially mill/machine the fabricated parts from aluminum stock, thenadopt metal casting, plastic molding, or composite fiber molding of thebody shell pieces to dramatically reduce per-unit prices. The milledpieces have high per-piece costs, but ongoing R&D can make changes oftenwithout any loss other than the part itself. The drawbacks to castingand molding are: the molds, dies and tooling are very expensivefront-loaded investments; the investment can be lost if the designchanges in a way that the tooling cannot accommodate; a cast metallicpart is structurally weaker than cold-rolled billet and heat treatedbillet; and a cast or molded part will still need secondary machining orprocessing for precision surface finishes, features, and thread tapping.Additional challenges to transitioning from milled to moldedconstruction include alterations to the part designs: features of thedesign must be changed to include outward draft angles in walls toprevent a mold die from sticking; small corner radiuses must beexpanded; undercuts may not be possible; and wall thickness must beregulated prevent improper lamination in composites or cure warping inplastic construction. The transition to a casting or molded constructionis more daunting for a product made of several body pieces becausemultiple molds and tooling sets must be created at once and tolerancestack-up can lead to parts which do not mate well. To be competitive involume manufacturing, the cost savings of cast and molded parts are anecessary step which can be very difficult and costly for prior artcomposed of multiple body pieces. If the quantity of parts to be cast ormolded could be reduced by integration, there would be fewer molds andassociated secondary machining and processing, as well as increasedreliability from fewer parts reducing tolerance stack-ups.

With a transition to casting or molding contemplated in theconceptualization stage-rather than the alpha or beta prototype releasestage—the benefits of a two-piece housing body are maximized. Becausethere are only two pieces to the housing, there are fewer molds andtooling than a comparable multi-piece design. This requires less capitalallocation in the early stages-before sales are supporting thedevelopment—thus the transition away from machining large billets can beinitiated sooner in the product life-cycle. Because there are only twopieces, there is less risk from warpage and tolerance stack-upspreventing precision alignment of bolt holes and mating flanges. Thepositioner housing 111 has only one mating flange to post machine, andfewer threads to tap for fastening the body shells together. The use ofmounting-holed turntable rings and—in some embodiments—removable shaftmounts negate secondary machining of precision bores and shoulders intoa cast metal piece's walls. Because the tilt shaft 105 has a more directkinetic path for load transfer between itself and the pan shaft base125, the body shell piece 111 is a superior structural member—not simplya housing—and continues to provide ample load bearing capacity withwalls no longer strengthened by heat treating and cold rolling of milledmetal stock. Because mold dies can require draft angles and minimizedundercuts to remove the die from the molded part, housing 111 in canaccommodate both milled and molded construction without significantmodification to the design. With reference to FIG. 30, housing 311 canhave outward drafted or vertical interior walls and can have outwardexterior wall drafts, and can have removable shaft mounts 128 and 145 tofacilitate the molding die and molding process. In FIG. 29, tilt shaftmounts can be integral features of the housing walls, but must notimpeded the action of a mold die or obstruct the installation of otherinternal components. Where even higher part integration can occur, aswith housing 111 of FIG. 10 which integrates pan bearing flange 129 withthe housing floor, it may be more economical and a device performancebenefit to avoid or shorten the machining prototype phase and insteaddevelop a cast metal rapid prototype which will be a closer step towardsthe traditional castings of full production. The adoption of themonocoque housing, enabled by the turntable bearing power train and wellcrafted assembly procedure, provides undeniably valuable benefits forperformance, cost and manufacturing time as it is realized in finishedgoods for sale.

It will be understood that the inventive system has been described withreference to particular embodiments; however additions, deletions andchanges could be made to these embodiments without departing from thescope of the inventive system. Although the order filling apparatus andmethod have been described include various components, it is wellunderstood that these components and the described configuration can bemodified and rearranged in various other configurations.

What is claimed is:
 1. A positioning device comprising: a housing havinga hollow center volume; a pan turntable bearing having an inner panring, an outer pan ring and a first plurality of bearings between theinner pan ring and the outer pan ring, the first plurality of bearingshaving four point contact with the inner pan ring and the outer panring, the pan turntable bearing rigidly coupled to a mounting; a panmotor that is rigidly coupled to the housing for rotating the housingabout the mounting; a tilt turntable bearing having an inner tilt ring,an outer tilt ring and a second plurality of bearings between the innertilt ring and the outer tilt ring, the second plurality of bearingshaving four point contact with the inner tilt ring and the outer tiltring; a tilt shaft that extends through a first side of the housing; atilt motor that is rigidly coupled to the housing for rotating the tiltshaft relative to the housing.
 2. The positioning device of claim 1further comprising: a pan gear coupled to the pan motor and the outerpan ring of the pan turntable bearing; and a pan belt mounted in tensionaround the outer pan ring and the pan gear; wherein rotation of the pangear by the pan motor causes rotation of the inner pan ring relative tothe outer pan ring and the mounting.
 3. The positioning device of claim2 further comprising: an adjustable pan motor mount for adjusting thetension in the pan belt.
 4. The positioning device of claim 1 furthercomprising: a tilt gear coupled to the tilt motor; and a tilt beltmounted in tension around the outer tilt ring and the tilt gear whereinrotation of the tilt gear by the tilt motor causes rotation of the tiltshaft.
 5. The positioning device of claim 4 further comprising: anadjustable tilt motor mount for adjusting the tension in the tilt belt.6. The positioning device of claim 1 wherein the tilt shaft extendsthrough the second side of the housing that is opposite the first sideof the housing.
 7. The positioning device of claim 1 further comprising:a tilt shaft flange surrounding the tilt shaft, an inner radial portionof the tilt shaft flange rigidly coupled to the tilt shaft and an outerradial portion of the tilt shaft flange rigidly coupled to the outertilt ring.
 8. The positioning device of claim 1 further comprising: atilt bearing flange surrounding the tilt shaft, an outer radial portionof the tilt bearing flange rigidly coupled to the housing and an innerradial portion of the tilt bearing flange rigidly coupled to the innertilt ring.
 9. The positioning device of claim 1 wherein the mounting isa pan shaft.
 10. The positioning device of claim 9 further comprising: apan shaft flange surrounding the pan shaft, an outer radial portion ofthe pan shaft flange rigidly coupled to the outer pan ring and an innerradial portion of the pan shaft flange rigidly coupled to the pan shaft.11. The positioning device of claim 1 further comprising: a pan bearingflange, an outer radial portion of the pan bearing flange rigidlycoupled to the housing and an inner radial portion of the pan bearingflange rigidly coupled to the inner pan ring.
 12. The positioning deviceof claim 1 wherein the pan bearing and the tilt bearing are pre-loadedto an elastic deformation of 0.00005 to 0.0006 inch.
 13. The positioningdevice of claim 1 further comprising: a tilt shaft actuator whichincludes the tilt motor and a tilt motor driver.
 14. The positioningdevice of claim 1 further comprising: a pan shaft actuator whichincludes the pan motor and pan motor driver.
 15. The positioning deviceof claim 1 wherein the tilt shaft includes a shaft coupler that allows afirst portion of the tilt shaft to rotate in misalignment with a secondportion of the tilt shaft, wherein the shaft coupler is between thefirst portion and the second portion.
 16. The positioning device ofclaim 1 further comprising: a clamp mechanism for releasably couplingthe pan shaft to a mounting fixture that supports the positioningdevice.
 17. The positioning device of claim 1 wherein the inner pan ringor the outer pan ring includes one or more alignment holes and alignmentpins are placed in the one or more alignment holes for preciselyaligning the pan turntable bearing with the housing.
 18. The positioningdevice of claim 1 wherein the inner tilt ring or the outer pan ringincludes one or more alignment holes and alignment pins are placed inthe one or more alignment holes for precisely aligning the pan turntablebearing with the housing.
 19. A positioning device comprising: a housinghaving a hollow center volume; a tilt bearing having an inner tilt ring,an outer tilt ring and a second plurality of bearings between the innertilt ring and the outer tilt ring, the second plurality of bearingshaving four point contact with the inner tilt ring and the outer tiltring, the inner tilt ring rigidly coupled to the housing; a tilt shaftthat extends through a first side of the housing, the tilt shaft rigidlycoupled to the outer tilt ring; a tilt motor that is rigidly coupled tothe housing for rotating of the tilt shaft relative to the housing. 20.The positioning device of claim 19 further comprising: a tilt gearcoupled to the tilt motor; and a tilt belt mounted in tension around theouter tilt ring and the tilt gear.
 21. The positioning device of claim20 further comprising: an adjustable tilt motor mount for adjusting thetension in the tilt belt.
 22. The positioning device of claim 19 furthercomprising: a second tilt bearing mounted between the housing and thetilt shaft.
 23. The positioning device of claim 19 wherein the tiltshaft extends through the second side of the housing that is oppositethe first side of the housing.
 24. The positioning device of claim 19further comprising: a tilt shaft flange surrounding the tilt shaft, aninner radial portion of the tilt shaft flange rigidly coupled to thetilt shaft and an outer radial portion of the tilt shaft flange rigidlycoupled to the outer tilt ring.
 25. The positioning device of claim 19further comprising: a tilt bearing flange surrounding the tilt shaft, anouter radial portion of the tilt bearing flange rigidly coupled to thehousing and an inner radial portion of the tilt bearing flange rigidlycoupled to the inner tilt ring.
 26. positioning device of claim 19wherein the pan bearing and the tilt bearing are pre-loaded to anelastic deformation of 0.0001 to 0.0006 inch.
 27. The positioning deviceof claim 19 further comprising: a tilt shaft actuator which includes thetilt motor and tilt motor driver.
 28. The positioning device of claim 19wherein the tilt shaft includes a shaft coupler that allows a firstportion of the tilt shaft to rotate in misalignment with a secondportion of the tilt shaft, wherein the shaft coupler is between thefirst portion and the second portion.